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                                                                     EXHIBIT 4.2

                        XM SATELLITE RADIO HOLDINGS INC.

                          EMPLOYEE STOCK PURCHASE PLAN

                                    ARTICLE I
                          PURPOSE AND SCOPE OF THE PLAN

1.1   Purpose

                  The XM Satellite Radio Holdings Inc. Employee Stock Purchase
Plan is intended to encourage employee participation in the ownership and
economic progress of the Corporation.

1.2   Definitions

Unless the context clearly indicates otherwise, the following terms have the
meaning set forth below:

"XM Benefits Administration" shall mean the Corporation's Human Resources Group.

"Board" shall mean the Board of Directors of the Corporation.

"Code" shall mean the Internal Revenue Code of 1986, as amended.

"Committee" shall mean a committee of officers or employees of the Corporation
and/or one or more of its Subsidiaries appointed by the Board, which Committee
shall administer the Plan as provided in Section 1.3 hereof.

"Common Stock" shall mean shares of Class A common stock, par value $.01 per
share, of the Corporation.

"Compensation" shall mean the base salary, bonuses, overtime, and commissions
paid to an Employee by the Corporation or a Subsidiary in accordance with
established payroll procedures.

"Corporation" shall mean XM Satellite Radio Holdings Inc.

"Covered Officer" shall mean an Employee who is subject to the reporting
requirements of Section 16(a) of the Exchange Act.

"Eligible Employee" shall mean an Employee who (i) is scheduled to work at least
20 hours per week and (ii) whose customary employment is more than five (5)
months in a calendar year.

"Employee" shall mean any employee of the Corporation or a Subsidiary.

"Exchange Act" shall mean the Securities Exchange Act of 1934, as amended.

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"Exercise Date" shall mean the date as determined by the Committee.

"Fair Market Value" of a share of Common Stock shall mean (i) with respect to
the Initial Offering Date, the price at which a share of Common Stock is sold to
the public in the Initial Public Offering, or (ii) in all other cases, the
amount equal to the average of the closing bid and asked for prices of a Share
on the applicable date as reported by the consolidated tape of the National
Association of Securities Dealers Automated Quotation (or on such other
recognized quotation system on which the trading prices of the Common Stock are
quoted on the applicable date), or, if no Share transactions are reported on
such tape (or such other system) on the applicable date, the average of the
closing bid and asked for prices of a Share on the immediately preceding date on
which Share transactions were so reported, or as determined pursuant to a
reasonable method adopted by the Committee in good faith for such purpose.

"Initial Offering" shall mean the first Option Period under the Plan, which
shall begin on the Initial Offering Date and shall end on December 31, 1999.

"Initial Offering Date" shall mean October 4, 1999.

"Offering Date" shall mean such date as shall be determined by the Committee in
accordance with the terms of the Plan.

"Option Period" shall mean (i) in the case of the Initial Offering, the period
beginning on the Initial Offering Date and ending on December 31, 1999, or (ii)
in all other cases, the period beginning on an Offering Date and ending on the
next succeeding Exercise Date.

"Option Price" shall mean the purchase price of a share of Common Stock
hereunder as provided in Section 3.1 hereof.

"Participant" shall mean any Eligible Employee who elects to participate.

"Plan" shall mean this XM Satellite Radio Holdings Inc. Employee Stock Purchase
Plan, as the same may be amended from time to time.

"Plan Account" shall mean an account established and maintained by the
Corporation in the name of each Participant.

"Plan Year" shall mean the twelve (12) month period beginning January 1 and
ending on the following December 31.

"Stock Purchase Agreement" shall mean the form prescribed by the Committee which
must be executed by an Employee who elects to participate in the Plan.

"Subsidiary" shall mean any company in which the Corporation owns, directly or
indirectly, shares possessing 50% of the total combined voting power of all
classes of stock.

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1.3   Administration of Plan

                  The Committee shall have the authority to administer the Plan
and to make and adopt rules and regulations not inconsistent with the provisions
of the Plan, provided that, except with respect to the Initial Offering, the
Committee also is authorized to change the Offering Periods, Offering Dates and
Exercise Dates under the Plan by providing written notice to all Employees at
least 15 days prior to the Exercise Date following which such changes will take
effect. The Committee shall adopt the form of Stock Purchase Agreement and all
notices required hereunder. The Committee may delegate administrative tasks
under the Plan to one or more agents. The Committee's interpretation and
decisions in respect to the Plan shall be final and conclusive.

1.4   Effective Date of Plan

                  The plan shall become effective on October 4, 1999, which
shall be the Initial Offering Date, provided that the Plan is approved by the
stockholders of the Corporation within 12 months before or after the date the
Plan is adopted by the Board.

1.5   Termination of Plan

                  The Plan shall continue in effect through December 31, 2009
unless terminated prior thereto pursuant to Section 4.3 hereof, or by the Board
which shall have the right to terminate the Plan at any time. Upon any such
termination, the balance of any payroll deductions in each Participant's Plan
Account shall be refunded and, except as provided in Article VI, a certificate
or certificates for any shares of Common Stock in each Participant's Plan
Account shall be distributed to the Participant.


                                   ARTICLE II
                                  PARTICIPATION

2.1   Eligibility

                  Except in the case of the Initial Offering, each person who is
an Eligible Employee on an Offering Date may become a Participant by executing
and filing a Stock Purchase Agreement at least 15 days prior to said Offering
Date. In the case of the Initial Offering, each person who is an Eligible
Employee on the Initial Offering Date may become a Participant by executing and
filing a Stock Purchase Agreement on or before the date determined by the
Committee in accordance with applicable law. An Employee may not participate in
the Plan if immediately after the applicable Offering Date or, in the case of
the Initial Offering, the Initial Offering Date, the Employee would be deemed
for purposes of Section 423(b)(3) of the Code to possess 5% or more of the total
combined voting power or value of all classes of stock of the Corporation or any
Subsidiary. Notwithstanding the foregoing, the eligibility of any Participant
who is a Covered Officer is further limited to the extent provided in Article
VI.

2.2   Payroll Deductions

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                  Payment for shares of Common Stock purchased hereunder shall
be made by authorized payroll deductions from each payment of Compensation in
accordance with instructions received from a Participant. Payroll deductions (a)
shall be equal to at least 1% of Compensation and (b) must equal at least five
dollars ($5.00) per pay period and (c) may be expressed either as (i) a whole
number percentage or (ii) a fixed dollar amount, subject to the provisions of
section 3.3 hereof. A Participant may not increase or decrease the deduction
during an Option Period. A Participant may, however, change the percentage
deduction for any subsequent Option Period by filing another Stock Purchase
Agreement at least 15 days prior to the Offering Date on which such subsequent
Option Period commences. Amounts deducted from a Participant's Compensation
pursuant to this Section 2.2 shall be credited to the Participant's Plan
Account.


                                   ARTICLE III
                               PURCHASE OF SHARES

3.1   Option Price

                  The Option Price of each share of the Common Stock shall be
determined by the Committee; PROVIDED, HOWEVER, that the Option Price per share
of the Common Stock sold to Participants hereunder shall be no less than 85% of
the Fair Market Value of such share on (i) in the case of the Initial Offering,
either the Initial Offering Date or the Exercise Date of the Option Period,
whichever is lower, or (ii) in all other cases, either the Offering Date or the
Exercise Date of the Option Period, whichever is lower, but in no event shall
the Option Price per share be less than the par value of the Common Stock.

3.2   Purchase of Shares

                  On each Exercise Date, the amount in a Participant's Plan
Account shall be charged with the aggregate Option Price of the largest number
of whole shares of Common Stock which can be purchased with said amount. The
balance, if any, in such Plan Account shall be carried forward to the next
succeeding Offering Period, unless the Participant has elected to withdraw from
the Plan pursuant to Section 5.1 hereof.

3.3   Limitations on Purchase

                  The Fair Market Value (determined on the Offering Date or the
Initial Offering Date, as the case may be) of the number of shares of Common
Stock that may be purchased under the Plan by a Participant in any calendar year
shall not exceed $25,000.

3.4   Transferability of Rights

                  Rights to purchase shares of Common Stock hereunder shall not
be transferable otherwise than by will or the laws of descent and distribution,
and may be exercised during the Participant's lifetime only by the Participant.


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                                   ARTICLE IV
                               PROVISIONS RELATING
                                 TO COMMON STOCK

4.1   Common Stock Reserved

                  There shall be 600,000 authorized and unissued shares of
Common Stock, reissued treasury shares of Common Stock, or shares of Common
Stock otherwise acquired by the Corporation, reserved for the Plan, subject to
adjustment in accordance with Section 4.2 hereof. The aggregate number of shares
which may be purchased under the Plan shall not exceed the number of shares
reserved for the Plan.

4.2   Adjustment for Changes in Common Stock

                  In the event that adjustments are made in the number of
outstanding shares of Common Stock or the shares are exchanged for a different
class of stock of the Corporation or for shares of stock of any other
corporation by reason of merger, consolidation, stock dividend, stock split or
otherwise, the Committee may make appropriate adjustments in (i) the number and
class of shares or other securities that may be reserved for purchase hereunder,
and (ii) the Option Price. All such adjustments shall be made in the sole
discretion of the Committee, and its decision shall be binding and conclusive.

4.3   Insufficient Shares

                  If the aggregate funds available for the purchase of Common
Stock on any Exercise Date would cause an issuance of shares in excess of the
number provided for in Section 4.1 hereof, (i) the Committee shall
proportionately reduce the number of shares that would otherwise be purchased by
each Participant in order to eliminate such excess, and (ii) the Plan shall
automatically terminate immediately after such Exercise Date.

4.4   Confirmation

                  Each purchase of Common Stock hereunder shall be confirmed in
writing to the Participant. A record of purchases shall be maintained by
appropriate entries on the books of the Corporation. Except as provided in
Article VI, Participants may obtain a certificate or certificates for all or
part of the shares of Common Stock purchased hereunder by requesting same in
writing.

4.5   Rights as Shareholders

                  The shares of Common Stock purchased by a Participant on an
Exercise Date shall, for all purposes, be deemed to have been issued and sold at
the close of business on such Exercise Date. Prior to that time, none of the
rights or privileges of a stockholder of the Corporation shall exist with
respect to such shares.

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                                    ARTICLE V
                          TERMINATION OF PARTICIPATION

5.1   Voluntary Withdrawal

                  A Participant may withdraw from the Plan at any time by filing
notice of withdrawal prior to the close of business on an Exercise Date. Upon
withdrawal, the entire amount, if any, in a Participant's Plan Account shall be
refunded to him or her, unless the Participant elects in such notice of
withdrawal to have such amount used to purchase whole shares of Common Stock
pursuant to Section 3.2 hereof on said Exercise Date, and have any remaining
balance refunded. Except as provided in Article VI with respect to Covered
Officers, any Participant who withdraws from the Plan may again become a
Participant in accordance with Section 2.1 hereof.

5.2   Termination of Eligibility

                  If a Participant retires, he or she may elect to (i) withdraw
the entire amount, if any, in his or her Plan Account, or (ii) have the amount
used to purchase whole shares of Common Stock pursuant to Section 3.2 hereof on
the next succeeding Exercise Date, and have any remaining balance refunded.

                  If a Participant ceases to be eligible under Section 2.1
hereof for any reason other than retirement, the dollar amount in such
Participant's Plan Account will be refunded and, except as provided in Article
VI, the number of unissued shares in such Participant's Plan Account will be
distributed to the Participant or his or her designated beneficiary or estate.


                                   ARTICLE VI
         SPECIAL RULES FOR COVERED OFFICERS AND CERTAIN RELATED MATTERS

6.1   Withdrawal From Plan

                  Unless permitted by the Committee, if a Participant who is a
Covered Officer withdraws from the Plan (I.E., ceases participation), he or she
will not again be eligible to participate in the Plan until the expiration of
six months from the effective date of the notice of withdrawal. In the event of
such withdrawal, the entire amount, if any, in the Participant's Plan Account
shall be refunded to him or her, unless the Participant elects in the notice of
withdrawal to purchase shares of Common Stock at the end of the Option Period
and have the balance, if any, in the Participant's Plan Account refunded (in
such case, the effective date of the notice of withdrawal will be the Exercise
Date).

6.2   Obtaining Certificates for Common Stock

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                  Unless otherwise permitted by the Committee, a Participant
shall not be permitted to receive a certificate or certificates representing
shares of Common Stock held in his or her Plan Account until the expiration of
six months from the Exercise Date on which the shares are purchased. If a
Participant withdraws from the Plan (I.E., ceases participation) or the Plan
terminates, and the Participant has shares of Common Stock in his or her Plan
Account that have not been held for such six-month period, no certificates for
the shares will be issued to the Participant until the end of that six-month
period unless the Committee so permits. Unless permitted by the Committee, if a
Participant who is a Covered Officer wishes to receive a certificate or
certificates representing shares of Common Stock that have been held in his or
her Plan Account for at least six months, the Participant also must withdraw
from the Plan (I.E., cease participation) as of the date the certificate or
certificates are issued and will not again be eligible to participate in the
Plan until the expiration of six months from that date.

6.3   Qualification under Code Section 423

                  Should any provision of this Article VI cause the Plan not to
qualify as an "employee stock purchase plan" within the meaning of Section 423
of the Code, then such provision shall not be a requirement under the Plan. In
that event, such provision shall instead be a guideline that each Participant
who is a Covered Officer is urged to follow in order to avoid possible liability
to the Corporation pursuant to Section 16(b) of the Exchange Act with respect to
transactions under the Plan.


                                   ARTICLE VII
                               GENERAL PROVISIONS

7.1   Broad Based, Nondiscriminatory Plan

                  The Plan shall at all times be a broad based,
nondiscriminatory plan within the meaning of Rule 16b-3(d)(2)(i)(A) under the
Exchange Act.

7.2   Notices

                  Any notice that a Participant files pursuant to the Plan shall
be made on forms prescribed by the Committee and, except with respect to a
notice of withdrawal that is intended to take effect after the purchase of
shares of Common Stock at the end of the Option Period (see Section 5.1 above),
shall be effective when received by XM Benefits Administration.

7.3   Condition of Employment

                  Neither the creation of the Plan nor participation therein
shall be deemed to create any right of continued employment or in any way affect
the right of the Corporation or a Subsidiary to terminate an Employee.

7.4   Amendment of the Plan

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                  The Board of Directors may at any time, or from time to time,
amend the Plan in any respect, except that, without approval of the
stockholders, no amendment may increase the aggregate number of shares reserved
under the Plan other than as provided in Section 4.2 hereof, materially increase
the benefits accruing to Participants, or modify the requirements as to
eligibility for participation in the Plan. Any amendment of the Plan must be
made in accordance with applicable provisions of the Code and/or any regulations
issued thereunder.

7.5   Application of Funds

                  All funds received by the Corporation by reason of purchase of
Common Stock hereunder may be used for any corporate purpose.

7.6   Legal Restrictions

                  The Corporation shall not be obligated to sell shares of
Common Stock hereunder if counsel to the Corporation determines that such sale
would violate any applicable law or regulation.

7.7   Governing Law

                  The Plan and all rights and obligations thereunder shall be
construed and enforced in accordance with the laws of the State of Delaware.


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                  The Plan was duly adopted and approved by the Board on
September 9, 1999, and was duly adopted and approved by the stockholders of the
Corporation on September 27, 1999. Amendments to the Plan were duly adopted and
approved by the Board on March 8, 2001 and duly adopted and approved by the
stockholders of the Corporation on May 24, 2001.


                                         /S/ JOSEPH M. TITLEBAUM
                                         ------------------------------------
                                         Joseph M. Titlebaum
                                         XM Satellite Radio Holdings Inc.
                                         Senior Vice President,
                                         General Counsel and Secretary