As filed with the Securities and Exchange Commission on August 4, 2005

Registration No. 333-         

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-3

REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

SIRIUS SATELLITE RADIO INC.

(Exact Name of Registrant as Specified in Its Charter)

1221 Avenue of the Americas, 36th Floor
New York, New York 10020
212-584-5100

(Address, Including Zip Code, and Telephone Number,
Including Area Code, of Registrant's Principal Executive Offices)

Patrick L. Donnelly
Executive Vice President, General Counsel and Secretary
Sirius Satellite Radio Inc.
1221 Avenue of the Americas, 36th Floor
New York, New York 10020
212-584-5100

(Name, Address, Including Zip Code, and Telephone Number,
Including Area Code, of Agent for Service)

Copy to:

Gary L. Sellers
Simpson Thacher & Bartlett LLP
425 Lexington Avenue
New York, New York 10017
212-455-2000

      Approximate date of commencement of proposed sale to the public: From time to time, after this Registration Statement becomes effective.

      If the only securities being registered on this form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. £

      If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, please check the following box. £

      If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. £                             

      If this form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. £                             

      If delivery of the prospectus is expected to be made pursuant to Rule 434, please check the following box. £

      (continued on next page)

CALCULATION OF REGISTRATION FEE

      This Registration Statement also constitutes Post-Effective Amendment No. 1 to Registration Statement No. 333-108387 and upon the effectiveness of such Post-Effective Amendment, this Registration Statement and Registration Statement No. 333-108387 will relate to an aggregate of $534,403,963 of Debt Securities, Preferred Stock, Common Stock and Warrants of Sirius Satellite Radio Inc.

      THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF THE SECURITIES ACT OF 1933 OR UNTIL THIS REGISTRATION STATEMENT SHALL BECOME EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a), MAY DETERMINE.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and we are not soliciting offers to buy these securities in any state where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED AUGUST 4, 2005

PROSPECTUS

$500,000,000

Debt Securities, Preferred Stock,
Common Stock and Warrants

We from time to time may offer:

at an aggregate initial public offering price not to exceed $500,000,000.

The number, amount, prices, net proceeds to Sirius Satellite Radio Inc. and specific terms of the securities will be determined at or before the time of sale and will be set forth in an accompanying prospectus supplement.

The net proceeds to us from the sale of the securities will be the initial public offering price or the purchase price of those securities less any applicable commission or discount, and less any other expenses we incur in connection with the issuance and distribution of those securities.

If any agents or any underwriters are involved in the sale of the foregoing securities, their names and any applicable commission or discount will be set forth in the accompanying prospectus supplement.

This prospectus may not be used for the sale of any securities unless it is accompanied by a prospectus supplement. The accompanying prospectus supplement may modify or supersede any statement in this prospectus.

NASDAQ National Market trading symbol: “SIRI”

      Investing in our securities involves risk, including the risks described in the documents incorporated by reference in this prospectus. You should carefully consider the important risk factors set forth under “Risk Factors” in the documents incorporated by reference in this prospectus and in the accompanying prospectus supplement before investing in our securities.

      Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is            , 2005.

TABLE OF CONTENTS

      You should rely only on the information contained in this prospectus, including the documents incorporated by reference and the other documents to which we have referred you. We have not authorized anyone to provide you with information that is different. This prospectus may only be used where it is legal to sell these securities. You should not assume that the information in this prospectus, any prospectus supplement or any document incorporated by reference is truthful or complete at any date other than the date mentioned on the cover page of these documents.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

      The following cautionary statements identify important factors that could cause our actual results to differ materially from those projected in the forward-looking statements made in this prospectus. Any statements about our beliefs, plans, objectives, expectations, assumptions or future events or performance are not historical facts and may be forward-looking. These statements are often, but not always, made through the use of words or phrases such as “will likely result,” “are expected to,” “will continue,” “is anticipated,” “estimated,” “intends,” “plans,” “projection” and “outlook.” These forward-looking statements are based on estimates and assumptions by our management that, although we believe to be reasonable, are inherently uncertain and subject to a number of risks and uncertainties. Any forward-looking statements are qualified in their entirety by reference to the factors discussed throughout this prospectus, and particularly the risk factors described under “Risk Factors” in this prospectus. Among the significant factors that could cause our actual results to differ materially from those expressed in the forward-looking statements are:

      Because the risk factors referred to above could cause actual results or outcomes to differ materially from those expressed in any forward-looking statements made by us or on our behalf, you should not place undue reliance on any of these forward-looking statements. In addition, any forward-looking statement speaks only as of the date on which it is made, and we undertake no obligation to update any forward-looking statement or statements to reflect events or circumstances after the date on which the statement is made, to reflect the occurrence of unanticipated events or otherwise. New factors emerge from time to time, and it is not possible for us to predict which will arise or to assess with any precision the impact of each factor on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements.

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ABOUT THIS PROSPECTUS

      This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, or the SEC, using a “shelf” registration process. Under this shelf registration process, we may sell any combination of the securities described in this prospectus in one or more offerings up to a total dollar amount of $500,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of the securities being offered. A prospectus supplement may include a discussion of any risk factors or other special considerations applicable to those securities or to us. The prospectus supplement may also add, update or change information contained in this prospectus. If there is any inconsistency between the information in this prospectus and the applicable prospectus supplement, you should rely on the information in the prospectus supplement. You should read both this prospectus and any prospectus supplement together with the additional information described under the headings “Where You May Find Additional Available Information About Us” and “Incorporation by Reference.”

ABOUT SIRIUS

      We are a leading provider of satellite radio in the United States. We currently offer more than 120 channels—65 channels of commercial-free music and over 55 channels of sports, news, talk, entertainment, traffic and weather programming to subscribers throughout the continental United States. The core of our enterprise is programming, and we are committed to creating the most unique, compelling and comprehensive entertainment experience on radio.

      Our 65 channels of commercial-free music are produced principally at our national broadcast studio in New York City and cover virtually every genre of music from classic rock, pop, heavy metal and hip-hop to country, dance, jazz, Latin and classical. Each of our 65 music channels is programmed and hosted by a team of experts. Our non-music channels include programming from major national news organizations, traffic and weather for America's top 20 markets and a number of other talk and entertainment channels, many of which are exclusively heard on SIRIUS.

      In October 2004, we announced that Howard Stern, one of the most widely listened to radio and entertainment personalities in the United States, will move his radio show to SIRIUS starting in January 2006.

      We are also the leading satellite radio provider of live sports programming. As the exclusive Satellite Radio Partner of the NFL, we feature live play-by-play coverage of all National Football League games. This breadth of NFL programming is not available on terrestrial radio or to our satellite radio competitor. We also broadcast play-by-play coverage of NBA games, college basketball and football games and will broadcast all the games of the NCAA Division I men's basketball tournament through 2007. We are also the official satellite radio broadcaster of Barclays English Premier League soccer and have the right to broadcast NHL games. In February 2005, we entered into an exclusive agreement with NASCAR to broadcast live all NASCAR Nextel Cup Series, NASCAR Busch Series and NASCAR Craftsmen Truck Series races for five years beginning in 2007.

      Our primary source of revenue is subscription fees, with most of our customers subscribing to SIRIUS on either a monthly or annual basis. In addition, we derive revenue from activation fees, selling advertising on our non-music channels, and the direct sale of SIRIUS radios and accessories. As of June 30, 2005, we had 1,814,626 subscribers.

      Our targeted subscriber market includes over 200 million registered vehicles, over 100 million households and over four million recreational boats in the United States.

      Subscribers receive our service through SIRIUS radios, which are sold by automakers, consumer electronics retailers, mobile audio dealers and other retailers or directly by us. Subscribers can also receive our music channels and certain other channels over the Internet and through DISH satellite television.

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      We expect an increasing proportion of our subscribers to be generated through our relationships with automakers. In 2005, SIRIUS radios are expected to be offered as a factory or dealer-installed option in over 100 car models, of which 65 models will offer SIRIUS as a factory-installed option. In certain of these arrangements, automakers have agreed to include a SIRIUS radio and a subscription to our service in the sale or lease price of vehicles. The length of these prepaid subscriptions vary, but it is typically six months to one year. We reimburse automakers for certain costs associated with the SIRIUS radio installed in the applicable vehicle at the time the vehicle is manufactured, including hardware costs and tooling expenses. We also pay revenue share and incentive-based commissions to automakers.

      We have exclusive agreements with DaimlerChrysler, Ford, Mitsubishi and BMW to offer SIRIUS radios as factory or dealer-installed equipment in Chrysler, Dodge, Jeep, Mercedes, Ford, Lincoln, Mercury, Volvo, Mazda, Jaguar, Land Rover, Mitsubishi, BMW and MINI vehicles and Freightliner and Sterling heavy trucks. We also have relationships with Nissan, Infiniti, Toyota, Lexus, Scion, Volkswagen and Audi, which permit these automakers to offer SIRIUS radios as factory or dealer-installed equipment.

      SIRIUS radios are marketed and distributed under various brands through major national and regional retailers, including Best Buy, Circuit City, Wal-Mart, RadioShack, Crutchfield, Office Depot, Sears, Target and DISH Network outlets, as well as local retailers. These retailers purchase SIRIUS radios directly from the manufacturers, and we do not receive revenues from retail sales of these radios. We develop in-store merchandising materials, including end-aisle displays for several retailers, and provide training for the sales forces of major retailers. We pay incentive-based commissions and residuals to certain retailers. Residuals are monthly fees paid based upon the number of subscribers using a SIRIUS radio purchased from a retailer.

      In June 2005, we announced an agreement with Sprint to provide select music channels to certain Sprint PCS subscribers.

      We are developing ancillary services that we expect to offer to subscribers in the future. These services include the delivery of traffic data to vehicles equipped with navigation systems, sports scores, weather data and other telematic functions. We also plan to commence broadcasting a limited number of video channels that will be designed and programmed principally for rear-seat video systems. We are working with a number of third parties to develop and design these services.

      We transmit our satellite broadcasts through our proprietary network which currently consists of three orbital satellites, 140 terrestrial repeaters that receive and retransmit our signal, and a satellite uplink facility. We also maintain a spare satellite which we can launch if necessary or desirable.

      We hold one of only two licenses issued by the Federal Communications Commission to provide satellite digital audio radio service in the United States. Our broadcasts are available across North America and some parts of Mexico and the Caribbean, although currently we do not offer subscriptions outside the continental United States.

      Sirius Satellite Radio Inc. was incorporated in the State of Delaware as Satellite CD Radio, Inc. on May 17, 1990. On December 7, 1992, we changed our name to CD Radio Inc., and we formed a wholly owned subsidiary, Satellite CD Radio, Inc., that is the holder of our FCC license. On November 18, 1999, we changed our name again to Sirius Satellite Radio Inc. Our executive offices are located at 1221 Avenue of the Americas, New York, New York 10020, our telephone number is (212) 584-5100 and our internet address is SIRIUS.com. SIRIUS.com is an inactive text reference only, meaning that the information contained on the website is not part of this prospectus and is not incorporated in this prospectus by reference.

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RISK FACTORS

      Investing in our securities involves risk, including the risks described in the accompanying prospectus supplement and in the documents incorporated by reference in this prospectus, including our Annual Report on Form 10-K for the year ended December 31, 2004, our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2005 and June 30, 2005, and in any filings made with the Securities and Exchange Commission after the date of this prospectus pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act. You should carefully consider the risk factors before investing in our securities.

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RATIO OF EARNINGS TO COMBINED FIXED CHARGES
AND PREFERRED STOCK DIVIDENDS

      The following table sets forth our ratios of (1) earnings to fixed charges and (2) earnings to combined fixed charges and preferred stock dividends for the periods indicated.

      The applicable ratio was less than 1.00 for all periods.

      The ratio of earnings to fixed charges is computed by dividing our earnings, which include income before taxes (excluding the cumulative and transition effects of accounting changes), fixed charges and amortization of capitalized interest, by fixed charges. The ratio of earnings to combined fixed charges and preferred stock dividends is computed by dividing earnings by the sum of fixed charges and dividends on preferred stock. “Fixed charges” consist of interest on debt and a portion of rentals determined to be representative of interest. For the years ended December 31, 2000, 2001, 2002, 2003 and 2004, and for the six months ended June 30, 2005 our earnings were insufficient to cover our fixed charges by $198.5 million, $255.0 million, $417.6 million, $214.6 million, $696.3 million, and $364.2 million, respectively. Earnings were also inadequate to cover our combined fixed charges and preferred stock dividends over the same time periods by $247.4 million, $297.2 million, $463.6 million, $302.8 million, $696.3 million and $364.2 million, respectively.

USE OF PROCEEDS

      Unless otherwise indicated in the applicable prospectus supplement, we expect to use the net proceeds from the sale of the offered securities for general corporate purposes. We may invest funds not required immediately for such purposes in short-term obligations or we may use them to reduce the future level of our indebtedness. Specific information concerning the use of proceeds from the sale of any securities will be included in the applicable prospectus supplement relating to such securities.

DESCRIPTION OF DEBT SECURITIES

      The following description of the terms of the debt securities sets forth certain general terms that may apply to the debt securities. The particular terms of any debt securities will be described in the prospectus supplement relating to those debt securities. For purposes of this “Description of Debt Securities,” the term “Sirius” refers to our company but not to any of its subsidiaries.

      Any senior debt securities will be issued in one or more series under an indenture, as supplemented or amended from time to time, between us and an institution that we will name in the related prospectus supplement, as trustee. Any senior subordinated securities will be issued in one or more series under an indenture, as supplemented or amended from time to time, between us and an institution that we will name in the related prospectus supplement, as trustee. Any subordinated debt securities will be issued in one or more series under an indenture, as supplemented or amended from time to time, between us and an institution that we will name in the related prospectus supplement, as trustee. For ease of reference, we will refer to the indenture relating to any senior debt securities as the senior indenture, the indenture relating to the senior subordinated debt securities as the senior subordinated indenture and to the indenture relating to any subordinated debt securities as the subordinated indenture.

      This summary of the terms and provisions of the debt securities and the indentures is not necessarily complete, and we refer you to the copy of the forms of the indentures which are filed

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as exhibits to the registration statement of which this prospectus forms a part. Whenever we refer to particular defined terms of the indentures in this section or in a prospectus supplement, we are incorporating these definitions into this prospectus or the prospectus supplement.

General

      The debt securities will be issuable in one or more series in accordance with an indenture supplemental to the applicable indenture or a resolution of our board of directors or a committee of the board. Unless otherwise specified in a prospectus supplement, each series of senior debt securities will rank equally in right of payment with all of our other senior obligations. Each series of senior subordinated debt securities will be subordinated and junior in right of payment to all senior indebtedness; pari passu with existing and future senior subordinated indebtedness; and senior to all existing and future subordinated indebtedness, in each case, to the extent and in the manner described in the senior subordinated debt indenture and any supplemental indenture relating to the senior subordinated debt securities. Each series of subordinated debt securities will be subordinated and junior in right of payment to the extent and in the manner described in the subordinated indenture and any supplemental indenture relating to the subordinated debt securities. Except as otherwise provided in a prospectus supplement, the indentures do not limit our ability to incur other secured or unsecured debt, whether under the indentures, any other indenture that we may enter into in the future or otherwise. For more information, you should read the prospectus supplement relating to a particular offering of securities.

      The applicable prospectus supplement will describe the following terms of the series of debt securities with respect to which this prospectus is being delivered:

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	•	any provision relating to the issuance of the debt securities at an original issue discount;
	•	the denominations in which any debt securities will be issuable, if other than denominations of $1,000 and any integral multiple thereof;
	•	the currency, currencies or currency units in which payment of principal of and any premium and interest on debt securities of the series shall be payable, if other than United States dollars;
	•	any index, formula or other method used to determine the amount of payments of principal of and any premium and interest on the debt securities;
	•	if the principal amount payable at the stated maturity of debt securities of the series will not be determinable as of any one or more dates before the stated maturity, the amount that will be deemed to be the principal amount as of any date for any purpose, including the principal amount thereof which will be due and payable upon any maturity other than the stated maturity or which will be deemed to be outstanding as of any date (or, in any such case, the manner in which the deemed principal amount is to be determined), and if necessary, the manner of determining the equivalent thereof in United States currency;
	•	if the principal of or any premium or interest on any debt securities is to be payable, at our election or the election of the holders, in one or more currencies or currency units other than that or those in which such debt securities are stated to be payable, the currency, currencies or currency units in which payment of the principal of and any premium and interest on such debt securities shall be payable, and the periods within which and the terms and conditions upon which such election is to be made;
	•	if other than the principal amount thereof, the portion of the principal amount of the debt securities which will be payable upon declaration of the acceleration of the maturity thereof or provable in bankruptcy;
	•	the applicability of, and any addition to or change in, the covenants and definitions then set forth in the applicable indenture or in the terms then set forth in such indenture relating to permitted consolidations, mergers or sales of assets;
	•	any changes or additions to the provisions of the applicable indenture dealing with defeasance, including the addition of additional covenants that may be subject to our covenant defeasance option;
	•	whether any of the debt securities are to be issuable in permanent global form and, if so, the depositary or depositaries for such global security and the terms and conditions, if any, upon which interests in such debt securities in global form may be exchanged, in whole or in part, for the individual debt securities represented thereby in definitive registered form, and the form of any legend or legends to be borne by the global security in addition to or in lieu of the legend referred to in the applicable indenture;
	•	the appointment of any trustee, any authenticating or paying agents, transfer agent or registrars;
	•	the terms, if any, of any guarantee of the payment of principal, premium and interest with respect to debt securities of the series and any corresponding changes to the provisions of the applicable indenture as then in effect;
	•	the terms, if any, of the transfer, mortgage, pledge or assignment as security for the debt securities of the series of any properties, assets, moneys, proceeds, securities or other collateral, including whether certain provisions of the Trust Indenture Act are applicable and any corresponding changes to provisions of the applicable indenture as then in effect;
	•	any addition to or change in the events of default with respect to the debt securities of the series and any change in the right of the trustee or the holders to declare the principal, premium and interest with respect to the debt securities due and payable;

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	•	any applicable subordination provisions in addition to those set forth herein with respect to senior subordinated debt securities or subordinated debt securities;
	•	any listing of the debt securities on any securities exchange;
	•	if the securities of the series are to be secured, the property covered by the security interest, the priority of the security interest, the method of perfecting the security interest and any escrow arrangements related to the security interest; and
	•	any other terms of the debt securities not inconsistent with the provisions of the applicable indenture.

      We may sell debt securities at a substantial discount below their stated principal amount or debt securities that bear no interest or bear interest at a rate which at the time of issuance is below market rates. We will describe the material United States federal income tax consequences, accounting and other special considerations applicable to the debt securities in the applicable prospectus supplement.

      If the purchase price of any of the debt securities is payable in one or more foreign currencies or currency units or if any debt securities are denominated in one or more foreign currencies or currency units or if the principal of, premium, if any, or interest, if any, on any debt securities is payable in one or more foreign currencies or currency units, we will set forth the restrictions, elections, specific terms and other information with respect to such issue of debt securities and such foreign currency or currency units in the applicable prospectus supplement.

Exchange, Registration, Transfer and Payment

      Unless otherwise indicated in the applicable prospectus supplement, principal, premium, if any, and interest, if any, on the debt securities will be issued in fully registered form and payable, without coupons, and the exchange of and the transfer of debt securities will be registrable, at our office or agency maintained for such purpose in the Borough of Manhattan, The City of New York and at any other office or agency maintained for such purpose. Unless otherwise indicated in the applicable prospectus supplement, the debt securities will be issued in denominations of $1,000 and any integral multiples thereof.

      Holders may present each series of debt securities for exchange as provided above, and for registration of transfer, with the form of transfer endorsed thereon, or with a satisfactory written instrument of transfer, duly executed, at the office of the appropriate securities registrar or at the office of any transfer agent designated by us for such purpose and referred to in the applicable prospectus supplement, without service charge and upon payment of any taxes and other governmental charges as described in the indenture. We will appoint the trustee of each series of debt securities as securities registrar for such series under the indenture. If the applicable prospectus supplement refers to any transfer agents, in addition to the securities registrar initially designated by us with respect to any series, we may at any time rescind the designation of any such transfer agent or approve a change in the location through which any such transfer agent acts, provided that we maintain a transfer agent in each place of payment for the series. We may at any time designate additional transfer agents with respect to any series of debt securities.

      All moneys paid by us to a paying agent for the payment of principal, premium, if any, or interest, if any, on any debt security which remain unclaimed for two years after such principal, premium or interest has become due and payable may be repaid to us, and after such time, the holder of such debt security may look only to us for payment.

Redemption

      Provisions relating to the redemption of debt securities, if any, will be set forth in the applicable prospectus supplement. Unless we state otherwise in the applicable propectus supplement, we may redeem debt securities only upon notice mailed at least 30 days but not more than 60 days before the date fixed for redemption.

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      In the event of any redemption, we shall not be required to (a) issue, register the transfer of or exchange debt securities of any series during a period beginning at the opening of business 15 days before the day of the mailing of a notice of redemption of debt securities of that series to be redeemed and ending at the close of business on the day of such mailing or (b) register the transfer of or exchange any debt security called for redemption, except, in the case of any debt securities being redeemed in part, any portion not being redeemed.

Book-Entry System

      The provisions set forth below in this section headed “Book-Entry System” will apply to the debt securities of any series if the prospectus supplement relating to such series so indicates.

      Unless otherwise indicated in the applicable prospectus supplement, the debt securities of such series will be represented by one or more global securities registered with a depositary named in the prospectus supplement relating to such series. Except as set forth below, a global security may be transferred, in whole but not in part, only to the depositary or another nominee of the depositary.

      The specific terms of the depositary arrangement with respect to a series of debt securities will be described in the prospectus supplement relating to the series. We anticipate that the following provisions will generally apply to depositary arrangements.

      Upon the issuance of a global security, the depositary will credit, on its book-entry registration and transfer system, the respective principal amounts of the debt securities represented by such global security to the accounts of institutions or persons, commonly known as participants, that have accounts with the depositary or its nominee. The accounts to be credited will be designated by the underwriters, dealers or agents. Ownership of beneficial interests in a global security will be limited to participants or persons that may hold interests through participants. Ownership of interests in such global security will be shown on, and the transfer of those ownership interests will be effected only through, records maintained by the depositary (with respect to participants' interests) and such participants (with respect to the owners of beneficial interests in such global security). The laws of some jurisdictions may require that certain purchasers of securities take physical delivery of the securities in definitive form. These limits and laws may impair the ability to transfer beneficial interests in a global security.

      So long as the depositary, or its nominee, is the registered holder and owner of such global security, the depositary or such nominee, as the case may be, will be considered the sole owner and holder for all purposes of the debt securities and for all purposes under the applicable indenture. Except as set forth below or as otherwise provided in the applicable prospectus supplement, owners of beneficial interests in a global security will not be entitled to have the debt securities represented by such global security registered in their names, will not receive or be entitled to receive physical delivery of debt securities in definitive form and will not be considered to be the owners or holders of any debt securities under the applicable indenture or such global security. Accordingly, each person owning a beneficial interest in a global security must rely on the procedures of the depositary and, if such person is not a participant, on the procedures of the participant through which such person owns its interest, to exercise any rights of a holder of debt securities under the applicable indenture of such global security. We understand that under existing industry practice, in the event we request any action of holders of debt securities or if an owner of a beneficial interest in a global security desires to take any action that the depositary, as the holder of such global security is entitled to take, the depositary would authorize the participants to take such action, and that the participants would authorize beneficial owners owning through such participants to take such actions or would otherwise act upon the instructions of beneficial owners owning through them.

      Payments of principal of and premium, if any, and interest, if any, on debt securities represented by a global security will be made to the depositary or its nominee, as the case may be, as the registered owner and holder of such global security, against surrender of the debt securities at the principal corporate trust office of the trustee. Interest payments will be made at

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the principal corporate trust office of the trustee or by a check mailed to the holder at its registered address. Payment in any other manner will be specified in the prospectus supplement.

      We expect that the depositary, upon receipt of any payment of principal, premium, if any, of interest, if any, in respect of a global security, will credit immediately participants' accounts with payments in amounts proportionate to their respective beneficial interests in the principal amount of such global security as shown on the records of the depositary. We expect that payments by participants to owners of beneficial interests in a global security held through such participants will be governed by standing instructions and customary practices, as is now the case with securities held for the accounts of customers in bearer form or registered in “street name,” and will be the responsibility of such participant. Neither Sirius nor the trustee nor any agent of Sirius or the trustee will have any responsibility or liability for any aspect of the records relating to, or payments made on account of, beneficial ownership interests in a global security or for maintaining, supervising or reviewing any records relating to such beneficial ownership interests or for any other aspect of the relationship between the depositary and its participants or the relationship between such participants and the owners of beneficial interests in such global security owning through such participants.

      Unless and until it is exchanged in whole or in part for debt securities in definitive form, a global security may not be transferred except as a whole by the depositary to a nominee of such depositary or by a nominee of such depositary to such depositary or another nominee of such depositary.

      Unless otherwise provided in the applicable prospectus supplement, debt securities represented by a global security will be exchangeable for debt securities in definitive form of like tenor as such global security in denominations of $1,000 and in any greater amount that is an integral multiple thereof if:

Any debt security that is exchangeable pursuant to the preceding sentence is exchangeable for debt securities registered in such names as the depositary shall instruct the trustee. It is expected that such instructions may be based upon directions received by the depositary from its participants with respect to ownership of beneficial interests in such global security. Subject to the foregoing, a global security is not exchangeable except for a global security or global securities of the same aggregate denominations to be registered in the name of the depositary or its nominee.

Covenants

      The covenants, if any, that will apply to a particular series of debt securities will be set forth in the indenture relating to such series of debt securities. Except as otherwise specified in the applicable prospectus supplement with respect to any series of debt securities, we may remove or add covenants without the consent of holders of the securities.

Discharge and Defeasance

      We may be discharged from our obligations on the debt securities of any series that have matured or will mature or be redeemed within one year if we deposit with the trustee enough cash to pay all the principal, interest and any premium due to the stated maturity date or

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redemption date of the debt securities and comply with certain other conditions set forth in the applicable indenture.

      In addition, each indenture contains a provision that permits us to elect either:

To make either of the above elections, we must deposit in trust with the trustee money and/or U.S. Government Obligations, if the debt securities are denominated in U.S. dollars, and/or Foreign Government Securities, if the debt securities are denominated in a foreign currency, which through the payment of principal and interest under their terms will provide sufficient money, without reinvestment, to repay in full those senior, senior subordinated or subordinated debt securities. As a condition to defeasance or covenant defeasance, we must deliver to the trustee an opinion of counsel that the holders of the debt securities will not recognize income, gain or loss for federal income tax purposes as a result of the defeasance.

      If either of the above events occur, the holders of the debt securities of the series will not be entitled to the benefits of the indenture, except for registration of transfer and exchange of debt securities and replacement of lost, stolen or mutilated debt securities.

Events of Default

      The following events are defined in the indentures as “Events of Default” with respect to a series of debt securities (unless such event is specifically inapplicable to a particular series as described in the applicable prospectus supplement):

      If an Event of Default for any series of debt securities occurs and continues, the trustee or holders of at least 25% in principal amount of the debt securities of that series may declare the entire principal amount of all the debt securities of that series to be due and payable immediately. Subject to certain conditions, the declaration may be annulled and past defaults (except uncured payment defaults and certain other specified defaults) may be waived by the holders of a majority of the principal amount of the outstanding debt securities of that series.

      An Event of Default for a particular series of debt securities does not necessarily constitute an event of default for any other series of debt securities issued under an indenture.

      Each indenture will require the trustee, within 90 days after the occurrence of a default known to it with respect to any outstanding series of debt securities, to give the holders of that series notice of the default if uncured or not waived. However, the trustee may withhold this notice if it determines in good faith that the withholding of this notice is in the interest of those holders, except that the trustee may not withhold this notice in the case of a payment default. The

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term “default” for the purpose of this provision means any event that is, or after notice or lapse of time or both would become, an Event of Default with respect to debt securities of that series.

      Other than the duty to act with the required standard of care during an Event of Default, a trustee is not obligated to exercise any of its rights or powers under the applicable indenture at the request or direction of any of the holders of debt securities, unless the holders have offered to the trustee reasonable indemnification. Each indenture provides that the holders of a majority in principal amount of outstanding debt securities of any series may in certain circumstances direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or other power conferred on the trustee.

      The senior indenture will include a covenant that we will file annually with the trustee a certificate of no default, or specifying any default that exists.

Modification, Waiver and Meetings

      We and the trustee may enter into supplemental indentures without the consent of the holders of debt securities for one or more of the following purposes:

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	•	to establish the form or terms of debt securities of any series;
	•	to provide for uncertificated debt securities in addition to or in place of certificated debt securities (provided that the uncertificated debt securities are issued in registered form for purposes of Section 163(f) of the Internal Revenue Code or in a manner such that the uncertificated debt securities are described in Section 163(f)(2)(B) of such Code); and
	•	to make any change that does not adversely affect the rights of any holder.

      Modifications and amendments of the applicable indenture may be made by us and the trustee with the consent of the holders of a majority in principal amount of the outstanding debt securities of each series affected by such modification or amendment; provided, however, that no such modification or amendment may, without the consent of the holder of each outstanding debt security affected thereby:

      The holders of a majority in principal amount of the outstanding debt securities of each series may, on behalf of the holders of all the debt securities of that series, waive, insofar as that series is concerned, compliance by us with certain restrictive provisions of the applicable indenture. The holders of a majority in principal amount of the outstanding debt securities of each series may, on behalf of all holders of debt securities of that series and any coupons relating to such series, waive any past default under the applicable indenture with respect to debt securities of the series, except a default (a) in the payment of principal of or any premium or interest on any debt security of such series or (b) in respect of a covenant or provision of the applicable indenture which cannot be modified or amended without the consent of each holder of outstanding debt securities of the affected series.

      The indentures provide that in determining whether the holders of the requisite principal amount of the outstanding debt securities have given any request, demand, authorization, direction,

14

notice, consent or waiver thereunder or whether a quorum is present at a meeting of holders of debt securities:

      In addition, we and the trustees may execute, without the consent of any holder of the debt securities, any supplemental indenture for the purpose of creating any new series of debt securities.

Subordination

      Except as set forth in the applicable prospectus supplement, the subordinated indenture provides that the subordinated debt securities are subordinate and junior in right of payment to all of our senior indebtedness. Except as set forth in the applicable prospectus supplement, the senior subordinated indenture provides that the senior subordinated debt securities will be subordinated and junior in right of payment to all senior indebtedness; pari passu with existing and future senior subordinated indebtedness; and senior to all existing and future subordinated indebtedness.

      If an Event of Default occurs with respect to any senior indebtedness permitting the holders thereof to accelerate the maturity thereof and the default is the subject of judicial proceedings or written notice of such Event of Default, requesting that payments on senior subordinated debt securities or subordinated debt securities cease, is given to us by the holders of senior indebtedness, then unless and until (1) the default in payment or Event of Default shall have been cured or waived or (2) 120 days shall have passed after written notice is given and the default is not the subject of judicial proceedings, no direct or indirect payment, in cash, property or securities, by set-off or otherwise, will be made or agreed to be made on account of the senior subordinated debt securities or subordinated debt securities or interest thereon or in respect of any repayment, redemption, retirement, purchase or other acquisition of senior subordinated debt securities or subordinate debt securities.

      Except as set forth in the applicable prospectus supplement, the senior subordinated indenture and the subordinated indenture provides that in the event of:

all present and future senior indebtedness, including interest accruing after the commencement of the proceeding, will first be paid in full before any payment or distribution, whether in cash, securities or other property, will be made by us on account of senior subordinated debt securities or subordinated debt securities. In that event, any payment or distribution, whether in cash, securities or other property, other than securities of Sirius or any other corporation provided for by a plan of reorganization or a readjustment, the payment of which is subordinated, at least to the extent provided in the subordination provisions of the indenture, to the payment of all senior indebtedness at the time outstanding and to any securities issued in respect thereof under any such plan of reorganization or readjustment and other than payments made from any trust described in the “Defeasance and Covenant Defeasance” above, which would otherwise but for the subordination provisions be payable or deliverable in respect of senior subordinated debt securities or subordinated debt securities, including any such payment or distribution which may be payable or deliverable by reason of the payment of any other indebtedness of ours being subordinated to

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the payment of senior subordinated debt securities or subordinated debt securities, will be paid or delivered directly to the holders of senior indebtedness or to their representative or trustee, in accordance with the priorities then existing among such holders, until all senior indebtedness shall have been paid in full. No present or future holder of any senior indebtedness will be prejudiced in the right to enforce subordination of the indebtedness evidenced by senior subordinated debt securites or subordinated debt securities by any act or failure to act on our part.

      The term “Senior Indebtedness” means:

(1) the principal, premium, if any, interest and all other amounts owed in respect of all our (A) indebtedness for money borrowed and (B) indebtedness evidenced by securities, debentures, bonds or other similar instruments;

(2) all our capital lease obligations;

(3) all our obligations issued or assumed as the deferred purchase price of property, all our conditional sale obligations and all our obligations under any title retention agreement (but excluding trade accounts payable arising in the ordinary course of business);

(4) all our obligations for the reimbursement of any letter of credit, banker's acceptance, security purchase facility or similar credit transaction;

(5) all obligations of the type referred to in clauses (1) through (4) above of other persons for the payment of which we are responsible or liable as obligor, guarantor or otherwise; and

(6) all obligations of the type referred to in clauses (1) through (5) above of other persons secured by any lien on any property or asset of ours (whether or not such obligation is assumed by us),

except for in all such cases (x) any such indebtedness that is by its terms subordinated to or pari passu with the senior subordinated debt securities or the subordinated debt securities and (y) any indebtedness between or among us or our affiliates, including all other debt securities and guarantees in respect of those debt securities issued to any trust, or trustee of such trust, partnership or other entity affiliated with us that is, directly or indirectly, a financing vehicle of ours (a “Financing Entity”) in connection with the issuance by such Financing Entity of preferred securities or other securities that rank pari passu with, or junior to, the senior subordinated debt securities or the subordinated debt securities.

      Except as provided in the applicable prospectus supplement, neither the senior subordinated indenture nor the subordinated indenture for a series of senior subordinated debt or subordinated debt, as the case may be, limits the aggregate amount of senior indebtedness that may be issued by us. Debt securities issued by us are structurally subordinated to all existing and future liabilities of our subsidiaries.

      By reason of such subordination, in the event of a distribution of assets upon insolvency, some of our general creditors may recover more, ratably, than holders of the senior subordinated debt securities and the subordinated debt securities.

      A senior subordinated indenture or a subordinated indenture may provide that the subordination provisions thereof will not apply to money and securities held in trust pursuant to the satisfaction and discharge and the legal defeasance provisions of the senior subordinated indenture or subordinated indenture, as the case may be.

      If this prospectus is being delivered in connection with the offering of a series of senior subordinated debt securities or subordinated debt securities, the accompanying prospectus supplement or the information incorporated by reference therein will set forth the approximate amount of senior indebtedness outstanding as of a recent date.

Consolidation, Merger and Sale of Assets

      Except as may otherwise be provided in the prospectus supplement, each indenture provides that we may not consolidate with or merge with or into any person, or convey, transfer or lease

16

all or substantially all of our assets, or permit any person to consolidate with or merge into us, unless the following conditions have been satisfied:

      Upon completion of any such transaction, the Successor Company resulting from such consolidation or into which we are merged or the transferee or lessee to which such conveyance, transfer or lease is made, will succeed to, and be substituted for, and may exercise every right and power of, us under each indenture, and thereafter, except in the case of a lease, the predecessor (if still in existence) will be released from its obligations and covenants under each indenture and all outstanding debt securities.

Notices

      Except as otherwise provided in the indentures, notices to holders of debt securities will be given by mail to the addresses of such holders as they appear in the security register.

Conversion or Exchange

      If and to the extent indicated in the applicable prospectus supplement, the debt securities of any series may be convertible or exchangeable into other securities. The specific terms on which debt securities of any series may be so converted or exchanged will be set forth in the applicable prospectus supplement. These terms may include provisions for conversion or exchange, either mandatory, at the option of the holder, or at our option, in which case the number of shares of other securities to be received by the holders of debt securities would be calculated as of a time and in the manner stated in the applicable prospectus supplement.

Title

      Before due presentment of a debt security for registration of transfer, we, the trustee and any agent of ours or the trustee may treat the person in whose name such debt security is registered as the owner of such debt security for the purpose of receiving payment of principal of and any premium and any interest (other than defaulted interest or as otherwise provided in the applicable prospectus supplement) on such debt security and for all other purposes whatsoever, whether or not such debt security be overdue, and neither Sirius, the trustee nor any agent of ours or the trustee shall be affected by notice to the contrary.

Replacement of Debt Securities

      Any mutilated debt security will be replaced by us at the expense of the holder upon surrender of such debt security to the trustee. Debt securities that become destroyed, stolen or lost will be replaced by us at the expense of the holder upon delivery to the trustee of the debt security or evidence of the destruction, loss or theft thereof satisfactory to us and the trustee. In the case of a destroyed, lost or stolen debt security, an indemnity satisfactory to the trustee and us

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may be required at the expense of the holder of such debt security before a replacement debt security will be issued.

Governing Law

      The indentures and the debt securities will be governed by, and construed in accordance with, the laws of the State of New York.

Regarding the Trustee

      We may appoint a separate trustee for any series of debt securities. As used herein in the description of a series of debt securities, the term “trustee” refers to the trustee appointed with respect to the series of debt securities.

      The indentures contain certain limitations on the right of the trustee, should it become a creditor of ours, to obtain payment of claims in certain cases or to realize for its own account on certain property received in respect of any such claim as security or otherwise. The trustee will be permitted to engage in certain other transactions; however, if it acquires any conflicting interest and there is a default under the debt securities of any series for which the trustee serves as trustee, the trustee must eliminate such conflict or resign.

      The trustee or its affiliate may provide certain banking and financial services to us in the ordinary course of business.

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DESCRIPTION OF CAPITAL STOCK

      Our amended and restated certificate of incorporation provides for authorized capital of 2,550,000,000 shares, consisting of 2,500,000,000 shares of common stock, par value $0.001 per share, and 50,000,000 shares of preferred stock, par value $0.001 per share.

      The following description sets forth the terms and provisions of our common stock and preferred stock. The terms of any shares of our capital stock offered by any prospectus supplement, but not set forth below, will be described in the prospectus supplement relating to such shares of capital stock.

Common Stock

      As of June 30, 2005, we had 1,326,747,936 shares of common stock outstanding beneficially held by approximately 900,000 holders, and had reserved for issuance approximately 505,000,000 shares of common stock with respect to incentive stock plans and outstanding common stock and warrants.

      Holders of our common stock are entitled to cast one vote for each share held of record on all matters acted upon at any stockholder's meeting and to receive dividends if, as and when declared by our board of directors out of funds legally available therefor. There are no cumulative voting rights. If there is any liquidation, dissolution or winding-up of our company, each holder of our common stock will be entitled to participate, taking into account the rights of any outstanding preferred stock, ratably in all of our assets remaining after payment of liabilities. Holders of our common stock have no preemptive or conversion rights. All shares of our common stock, including shares of common stock issued upon the exercise of the common stock warrants and options, will be fully paid and non-assessable, when issued.

      Our common stock is quoted on the NASDAQ National Market under the symbol “SIRI.”

Preferred Stock

      Our board of directors is authorized, subject to any limitations prescribed by law, without further stockholder approval, to issue from time to time up to an aggregate of 50,000,000 shares of our preferred stock, in one or more series. As of June 30, 2005, there were no preferred shares issued or outstanding. Each such series of preferred stock will have such number of shares, designations, preferences, powers, qualifications and special or relative rights or privileges as will be determined by our board of directors, which may include, among others, dividend rights, voting rights, redemption and sinking fund provisions, liquidation preferences, conversion rights and preemptive rights. The rights of the holders of our common stock will be subject to the rights of holders of any preferred stock issued in the future. The issuance of preferred stock, while providing desirable flexibility in connection with possible acquisitions and other corporate purposes, could have the effect of making it more difficult for a third party to acquire, or of discouraging a third party from acquiring, a majority of our outstanding voting stock.

      The specific terms of any preferred stock being offered will be described in the prospectus supplement relating to that preferred stock. The following summaries of the provisions of the preferred stock are subject to, and are qualified in their entirety by reference to, the certificate of designation relating to the particular class or series of preferred stock. Reference is made to the prospectus supplement relating to the preferred stock offered with that prospectus for specific terms, including:

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	•	the place or places where dividends will be paid, whether dividends will be cumulative or noncumulative, and, if cumulative, the date from which dividends on the preferred stock will accumulate, if applicable;
	•	the procedures for any auction and remarketing of the preferred stock;
	•	the provision of a sinking fund, if any, for the preferred stock;
	•	the provision for redemption, if applicable, of the preferred stock;
	•	any listing of the preferred stock on any securities exchange;
	•	the terms and conditions, if applicable, upon which the preferred stock will be convertible into or exchangeable for common stock, and whether at our option or the option of the holder;
	•	whether the preferred stock will rank senior or junior to or on a parity with any other class or series of preferred stock;
	•	the voting rights, if any, of the preferred stock;
	•	any other specific terms, preference, rights, limitations or restrictions of the preferred stock; and
	•	a discussion of United States federal income tax considerations applicable to the preferred stock.

Delaware Anti-Takeover Law and Provisions in Our Amended and Restated Certificate of Incorporation

      Section 203 of the Delaware General Corporation Law (“Section 203”) generally provides that a stockholder acquiring more than 15% of the outstanding voting stock of a corporation subject to the statute (an “Interested Stockholder”) but less than 85% of this stock may not engage in some types of Business Combinations (as defined in Section 203) with the corporation for a period of three years after the time the stockholder became an Interested Stockholder. The prohibition of Section 203 does not apply under the following circumstances:

      Under Section 203, these restrictions will not apply to specific Business Combinations proposed by an Interested Stockholder following the earlier of the announcement or notification of specific extraordinary transactions involving the corporation and a person who was not an Interested Stockholder during the previous three years, who became an Interested Stockholder with the approval of the corporation's board of directors or who became an Interested Stockholder at a time when the restrictions contained in Section 203 did not apply for reasons specified in Section 203. The above exception applies if the extraordinary transaction is approved or not opposed by a majority of the directors who were directors prior to the person becoming an Interested Stockholder during the previous three years or were recommended for election or elected to succeed those directors by a majority of those directors.

      Section 203 defines the term “Business Combination” to encompass a wide variety of transactions with or caused by an Interested Stockholder. These include transactions in which the Interested Stockholder receives or could receive a benefit on other than a pro rata basis with other stockholders, transactions with the corporation which increase the proportionate interest in the corporation directly or indirectly owned by the Interested Stockholder or transactions in which the Interested Stockholder receives other benefits.

      The provisions of Section 203, coupled with our board of directors' authority to issue preferred stock without further stockholder action, could delay or frustrate the removal of

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incumbent directors or a change in our control. The provisions could also discourage, impede or prevent a merger, tender offer or proxy contest, even if the event would be favorable to the interests of stockholders. Our stockholders, by adopting an amendment to our amended and restated certificate of incorporation, may elect not to be governed by Section 203 effective 12 months after the adoption.

DESCRIPTION OF WARRANTS

      We may issue warrants for the purchase of debt securities, preferred stock, common stock or any combination thereof. Warrants may be issued independently or together with any other securities offered in an applicable prospectus supplement and may be attached to or separate from such securities. Warrants may be issued under warrant agreements (each, a “warrant agreement”) to be entered into between us and a warrant agent specified in the applicable prospectus supplement. The warrant agent will act solely as our agent in connection with the warrants of a particular series and will not assume any obligation or relationship of agency or trust for or with any holders or beneficial owners of warrants. The following sets forth certain general terms and provisions of warrants which may be offered. Further terms of the warrants and the applicable warrant agreement will be set forth in an applicable prospectus supplement.

Debt Warrants

      The prospectus supplement relating to a particular issue of warrants for the purchase of debt securities (“debt warrants”) will describe the terms of the debt warrants, including the following:

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Stock Warrants

      The prospectus supplement relating to a particular issue of warrants for the purchase of common stock or preferred stock will describe the terms of the warrants, including the following:

Exercise of Warrants

      Each warrant will entitle the holder of warrants to purchase for cash the amount of shares of preferred stock, shares of common stock or debt securities at the exercise price as shall in each case be set forth in, or be determinable as set forth in, the prospectus supplement relating to the warrants offered thereby. Warrants may be exercised at any time up to the close of business on the expiration date set forth in the prospectus supplement relating to the warrants offered thereby. After the close of business on the expiration date, unexercised warrants will become void.

      Warrants may be exercised as set forth in the prospectus supplement relating to the warrants offered thereby. Upon receipt of payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the prospectus supplement, we will, as soon as practicable, forward the shares of preferred stock, shares of common stock or debt securities purchasable upon such exercise. If less than all of the warrants represented by the warrant certificate are exercised, a new warrant certificate will be issued for the remaining warrants.

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PLAN OF DISTRIBUTION

      We may sell the securities:

      • to one or more underwriters or dealers for public offering and sale by them; and

      • to investors directly or through agents.

      The distribution of securities may be effected from time to time in one or more transactions at a fixed price or prices (which may be changed from time to time), at market prices prevailing at the time of sale, at prices related to such prevailing market prices or at negotiated prices. Each prospectus supplement will describe:

      • the method of distribution of the securities offered thereby;

      • the purchase price and the proceeds we will receive from the sale; and

      • any securities exchanges on which the securities of such series may be listed.

      In connection with the sale of the securities, underwriters, dealers or agents may receive compensation from us or from purchasers of the securities for whom they may act as agents, in the form of discounts, concessions or commissions. The underwriters, dealers or agents that participate in the distribution of the securities may be deemed to be underwriters under the Securities Act and any discounts or commissions received by them and any profit on the resale of the securities received by them may be deemed to be underwriting discounts and commissions thereunder. Any such underwriter, dealer or agent will be identified and any such compensation received from us will be described in the applicable prospectus supplement. Any initial public offering price and any discounts or concessions allowed or paid to dealers may be changed from time to time.

      Under the agreements that may be entered into with us, underwriters, dealers and agents may be entitled to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, or to contribution with respect to payments which the underwriters, dealers or agents may be required to make in respect thereof.

      Each underwriter, dealer and agent participating in the distribution of any securities that are issuable in bearer form will agree that it will not offer, sell, resell or deliver, directly or indirectly, securities in bearer form to persons located in the United States or to United States persons (other than qualifying financial institutions), in connection with the original issuance of the securities.

      Certain of the underwriters or agents and their associates may be customers of, engage in transactions with and perform services for us in the ordinary course of business.

      Certain persons participating in an offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities, including over-allotment, stabilizing and short-covering transactions in such securities, the imposition of a penalty bid, and bidding for and purchasing shares of our common stock in the open market during and after an offering.

LEGAL MATTERS

      Simpson Thacher & Bartlett LLP, New York, New York, will pass upon specific legal matters under state law with respect to the validity of the securities.

EXPERTS

INCORPORATION BY REFERENCE

      The SEC allows us to “incorporate by reference” in this prospectus other information we file with them, which means that we can disclose important information to you by referring you to those documents. This prospectus incorporates important business and financial information about us that is not included in or delivered with this prospectus. The information we file later with the SEC will automatically update and supersede the information included in and incorporated by reference in this prospectus. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus. We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act until we sell all the securities covered by this prospectus.

1. Our Annual Report on Form 10-K for the year ended December 31, 2004.

2. Our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2005 and June 30, 2005.

3. The description of our common stock contained in our Registration Statement on Form 8-A filed pursuant to Section 12(g) of the Exchange Act.

      We have filed each of these documents with the SEC and they are available from the SEC's internet site and public reference rooms described under “Where You May Find Additional Available Information About Us” in this prospectus. You may also request a copy of these filings, at no cost, by writing or calling us at the following address or telephone number:

Patrick L. Donnelly
Executive Vice President, General Counsel and Secretary
Sirius Satellite Radio Inc.
1221 Avenue of the Americas, 36th Floor
New York, New York 10020
(212) 584-5100

      You should rely only on the information incorporated by reference or provided in this prospectus or any prospectus supplement. We have not authorized anyone else to provide you with different information.

WHERE YOU MAY FIND ADDITIONAL AVAILABLE INFORMATION ABOUT US

      We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any of these reports, statements or other information at the SEC's public reference room at 100 F Street, N.E., Washington, D.C. 20549 or at its regional offices. You can request copies of those documents, upon payment of a duplicating fee, by writing to the SEC. Please call the SEC at 1-800-SEC-0330 for further information on the public reference rooms. Our SEC filings are also available to the public at the SEC's internet site at http://www.sec.gov.

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$500,000,000

Debt Securities, Preferred Stock,
Common Stock and Warrants

         , 2005

PART II
INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.

      The following table sets forth all expenses, other than the underwriting discounts and commissions, payable by the Registrant in connection with the sale of the securities being registered. All the amounts shown are estimates except for the Securities and Exchange Commission registration fee and the NASD filing fee.

Item 15. Indemnification of Officers and Directors.

      Section 145 of the DGCL permits each Delaware business corporation to indemnify its directors, officers, employees and agents against liability for each such person's acts taken in his or her capacity as a director, officer, employee or agent of the corporation if such actions were taken in good faith and in a manner which he or she reasonably believed to be in or not opposed to the best interests of the corporation, and with respect to any criminal action, if he or she had no reasonable cause to believe his or her conduct was unlawful. Article VII of our amended and restated by-laws provides that we, to the full extent permitted by Section 145 of the DGCL, shall indemnify all of our past and present directors and may indemnify all of our past or present employees or other agents. To the extent that a director, officer, employee or agent of ours has been successful on the merits or otherwise in defense of any action, suit or proceeding referred to in such Article VII, or in defense of any claim, issue or matter therein, he or she shall be indemnified by us against actually and reasonably incurred expenses in connection therewith. Such expenses may be paid by us in advance of the final disposition of the action upon receipt of an undertaking to repay the advance if it is ultimately determined that such person is not entitled to indemnification.

      As permitted by Section 102(b)(7) of the DGCL, our amended and restated certificate of incorporation provides that no director shall be liable to us for monetary damages for breach of fiduciary duty as a director, except for liability:

      We have obtained a policy insuring us and our directors and officers against certain liabilities, including liabilities under the Securities Act.

II-1

Item 16. Exhibits.

II-2

Exhibit Number		Description
4.13	—	Third Supplemental Indenture, dated as of March 7, 2003, between the Company and HSBC Bank USA, as trustee, relating to the Company's 83⁄4% Convertible Subordinated Notes due 2009 (incorporated by reference to Exhibit 4.17 to the Company's Annual Report on Form 10-K for the year ended December 31, 2002).
4.14	—	Form of 83⁄4% Convertible Subordinated Note due 2009 (incorporated by reference to Article VII of Exhibit 4.01 to the Company's Current Report on Form 8-K filed on October 1, 1999).
4.15	—	Indenture, dated as of May 23, 2003, between the Company and The Bank of New York, as trustee, relating to senior indebtedness of the Company (incorporated by reference to Exhibit 99.2 to the Company's Current Report on Form 8-K dated May 30, 2003).
4.16	—	Supplemental Indenture, dated as of May 23, 2003, between the Company and The Bank of New York, as trustee, relating to the Company's 31⁄2% Convertible Notes due 2008 (incorporated by reference to Exhibit 99.3 to the Company's Current Report on Form 8-K dated May 30, 2003).
4.17	—	Form of 31⁄2% Convertible Note due 2008 (incorporated by reference to Exhibit A of Exhibit 99.3 to the Company's Current Report on Form 8-K dated May 30, 2003).
4.18	—	Second Supplemental Indenture, dated as of February 20, 2004, between the Company and The Bank of New York, as trustee, relating to the Company's 21⁄2% Convertible Notes due 2009 (incorporated by reference to Exhibit 4.20 to the Company's Annual Report on Form 10-K for the year ended December 31, 2003).
4.19	—	Form of 21⁄2% Convertible Notes due 2009 (incorporated by reference to Exhibit 4.22 to the Company's Registration Statement on Form S-3 (File No. 333-115695)).
4.20	—	Third Supplemental Indenture, dated as of October 13, 2004, between the Company and The Bank of New York, as trustee, relating to the Company's 31⁄4% Convertible Notes due 2011 (incorporated by reference to Exhibit 4.1 to the Company's Current Report on Form 8-K dated October 13, 2004).
4.21	—	Common Stock Purchase Warrant granted by the Company to DaimlerChrysler AG dated October 25, 2002 (incorporated by reference to Exhibit 4.20 to the Company's Quarterly Report on Form 10-Q for the quarter ended September 30, 2002).
4.22	—	Form of Media-Based Incentive Warrant dated February 3, 2004 issued by the Company to NFL Enterprises LLC (incorporated by reference to Exhibit 4.25 to the Company's Annual Report on Form 10-K for the year ended December 31, 2003).
4.23	—	Bounty-Based Incentive Warrant dated February 3, 2004 issued by the Company to NFL Enterprises LLC (incorporated by reference to Exhibit 4.26 to the Company's Annual Report on Form 10-K for the year ended December 31, 2003).
4.24	—	Amended and Restated Warrant Agreement, dated as of December 27, 2000, between the Company and United States Trust Company of New York, as warrant agent and escrow agent (incorporated by reference to Exhibit 4.27 to the Company's Registration Statement on Form S-3 (File No. 333-65602)).
4.25	—	Second Amended and Restated Pledge Agreement, dated as of March 7, 2001, among the Company, as pledgor, The Bank of New York, as trustee and collateral agent, United States Trust Company of New York, as trustee, and Lehman Commercial Paper Inc., as administrative agent (incorporated by reference to Exhibit 4.25 to the Company's Quarterly Report on Form 10-Q for the quarter ended September 30, 2001).
4.26	—	Amended and Restated Intercreditor Agreement, dated as of March 7, 2001, by and between The Bank of New York, as trustee and collateral agent, United States Trust Company of New York, as trustee, and Lehman Commercial Paper Inc., as administrative agent (incorporated by reference to Exhibit 4.27 to the Company's Quarterly Report on Form 10-Q for the quarter ended September 30, 2001).

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Exhibit Number		Description
4.27	—	Form of Subordinate Indenture (incorporated by reference to Exhibit 4.6.2 to the Company's Registration Statement on Form S-3 (File No. 333-86003)).
5.1	—	Opinion of Simpson Thacher & Bartlett LLP regarding legality.**
12.1	—	Statement re: Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends.*
23.1	—	Consent of Independent Registered Public Accounting Firm.*
23.2	—	Consent of Simpson Thacher & Bartlett LLP (included in Exhibit 5.1).
24.1	—	Powers of Attorney (included on signature page).*
25.1	—	Statement of Eligibility and Qualification on Form T-1 of the Trustee to act as Trustee under the Indenture.**

*		Filed herewith.
**		To be filed by amendment or by a Current Report on Form 8-K in accordance with Regulation S-K, Item 601(b).

Item 17. Undertakings

      The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

provided, however, that paragraphs (1)(i) and (1)(ii) do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in periodic reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant's annual report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each

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	filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.
	(5) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to provisions described in Item 15, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer of controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

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SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York, State of New York, on August 4, 2005.

POWER OF ATTORNEY

      We, the undersigned directors and officers of the registrant, do hereby constitute and appoint Patrick L. Donnelly and Ruth A. Ziegler, or either of them, our true and lawful attorneys and agents, to do any and all acts and things in our name and on our behalf in our capacities as directors and officers and to execute any and all instruments for us and in our names in the capacities indicated below, which said attorneys and agents, or either of them, may deem necessary or advisable to enable the registrant to comply with the Securities Act and any rules, regulations and requirements of the SEC, in connection with this registration statement, including specifically, but without limitation, power and authority to sign for us or any of us in our names in the capacities indicated below, any and all amendments (including post-effective amendments) hereto, and we do hereby ratify and confirm all that said attorneys and agents, or either of them, shall do or cause to be done by virtue hereof.

      Pursuant to the requirements of the Securities Act, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

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/s/ JAMES P. HOLDEN         James P. Holden		Director		August 4, 2005
/s/ WARREN N. LIEBERFARB       Warren N. Lieberfarb		Director		August 4, 2005
/s/ MICHAEL MCGUINESS       Michael McGuiness		Director		August 4, 2005
/s/ JAMES F. MOONEY       James F. Mooney		Director		August 4, 2005

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