As filed with the Securities and Exchange Commission on June 20, 2003
                                                      Registration No. 333-_____
===============================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933

                             XO COMMUNICATIONS, INC.
             (Exact name of registrant as specified in its charter)

           Delaware                                            54-1983517
  (State or other jurisdiction                              (I.R.S. Employer
of incorporation or organization)                       Identification Number)

                             11111 Sunset Hills Road
                             Reston, Virginia 20190
          (Address, including zip code, of principal executive offices)

                ------------------------------------------------
                             XO Communications, Inc.
                            2002 Stock Incentive Plan
                            (Full title of the plan)
                ------------------------------------------------

                               Wayne M. Rehberger
                Executive Vice President, Chief Financial Officer
                             XO Communications, Inc.
                             11111 Sunset Hills Road
                             Reston, Virginia 20190
                                 (703) 547-2000

    (Name, address, including zip code, and telephone number, including area
                           code, of agent for service)

                ------------------------------------------------
                                    Copies to
                              Bruce R. Kraus, Esq.
                            Willkie Farr & Gallagher
                               787 Seventh Avenue
                               New York, NY 10019
                                 (212) 728-8000
                ------------------------------------------------

                         CALCULATION OF REGISTRATION FEE

================================================================================
    Title of       Amount to be       Proposed        Proposed       Amount of
securities to be  registered (1)      maximum         maximum      registration
   registered                      offering price    aggregate          fee
                                        per           offering
                                     Option (2)      price (2)
--------------------------------------------------------------------------------
Options to
purchase and Stock
Appreciation
Rights relating
to Common
Stock, $0.01 par     1,900,000          N/A        $10,708,067.00     $866.28
value per share
===============================================================================

     (1) This Registration Statement covers the offer and sale of options to
purchase ("Options") and stock appreciation rights relating to ("SARs") an
aggregate of 1,900,000 shares of the common stock of XO Communications, Inc.,
$0.01 par value per share, issuable pursuant to the XO Communications, Inc. 2002
Stock Incentive Plan (the "Plan") through awards granted under the XO
Communications, Inc. 2003 Employee Retention and Incentive Plan (the "Retention
Plan"). In addition, this Registration Statement covers an indeterminable number
of additional Options and SARs as may hereafter be offered or issued pursuant to
the Plan, to prevent dilution resulting from stock splits, stock dividends or
similar transactions effected without receipt of consideration and pursuant to
Rule 416(c) under the Securities Act of 1933, as amended (the "Securities Act").

     (2) Estimated solely for calculating the amount of the registration fee.
The registration fee has been calculated based on the aggregate potential cash
awards that the Option and SAR recipients may elect to waive in order to have
the opportunity to earn Option and SAR awards under the Retention Plan.


<PAGE>


                                     PART II

                           INFORMATION REQUIRED IN THE
                             REGISTRATION STATEMENT

Item 3. INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

     The following documents, filed with the Securities and Exchange Commission
(the "Commission") by XO Communications, Inc., a Delaware corporation (the
"Company"), are incorporated by reference into this Registration Statement:

          (a) the Company's Annual Report on Form 10-K for the fiscal year ended
     December 31, 2002, filed pursuant to the Securities Exchange Act of 1934
     (the "Exchange Act");

          (b) the Company's Quarterly Report on Form 10-Q for the quarter ended
     March 31, 2003, filed pursuant to the Exchange Act; and

          (c) the Company's Current Reports on Form 8-K, filed on May 19, 2003,
     June 6, 2003 and June 13, 2003 pursuant to the Exchange Act;

     In addition, all documents filed by the Company with the Commission
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent
to the date of the Registration Statement and prior to the filing of a
post-effective amendment which indicates that all the securities offered hereby
have been sold or which deregisters all securities then remaining unsold shall
be deemed to be incorporated herein by reference and to be a part hereof from
the date of the filing of such documents with the Commission.

     THE COMPANY WILL PROVIDE WITHOUT CHARGE, UPON WRITTEN OR ORAL REQUEST, A
COPY OF ANY OR ALL OF THE FOREGOING DOCUMENTS INCORPORATED HEREIN BY REFERENCE
(OTHER THAN EXHIBITS TO SUCH DOCUMENTS). IN ADDITION, THE COMPANY WILL PROVIDE
ALL DOCUMENTS REQUIRED TO BE DELIVERED TO PARTICIPANTS PURSUANT TO RULE 428(b)
OF THE SECURITIES ACT. REQUESTS FOR SUCH DOCUMENTS SHOULD BE DIRECTED TO GENERAL
COUNSEL, XO COMMUNICATIONS, INC., 11111 SUNSET HILLS ROAD, RESTON, VIRGINIA
20190, (703) 547-2000.

Item 4. DESCRIPTION OF SECURITIES

     The Options are options to purchase shares of the Company's common stock,
$0.01 par value per share (the "Common Stock"), to be issued pursuant to the
Company's 2002 Stock Incentive Plan as a result of awards granted under the
Company's 2003 Employee Retention and Incentive Plan (the "Retention Plan"). A
SAR gives the recipient the right to exercise the SAR and receive a cash amount
equal to the excess of the fair market value of one share of Common Stock on the
date of exercise over the exercise price stated in the SAR multiplied by the
number of shares with respect to which the SAR is being exercised. Options and
SARs covering an aggregate of 1,900,000 shares of Common Stock have been
authorized for issuance by the Company. Pursuant to the terms of the Retention
Plan, except as set forth below for Options and SARs granted to terminating
employees, Options and SARs will be granted (i) upon the completion of the
Company's second fiscal quarter of 2003 (the "Second Quarter Awards") and (ii)
upon the attainment of certain year-end Company revenue and cash balance goals
following the end of fiscal 2003 (the "Fourth Quarter


<PAGE>


Awards"). The Second Quarter Awards will be fifty percent (50%) vested and
exercisable on the date of grant, with the remaining fifty percent (50%) vesting
ratably every month for twenty four (24) months following the month of grant.
The Fourth Quarter Awards will be twenty-five percent (25%) vested and
exercisable on the date of grant, with the remaining seventy-five percent (75%)
vesting ratably every month for thirty-six (36) months following the month of
grant. Vesting of the Options and SARs is subject to continued employment with
the Company or a subsidiary on the respective vesting dates.

     Participants in the Retention Plan who terminate employment with the
Company and its subsidiaries prior to the end of either the second fiscal
quarter of 2003 or the fourth fiscal quarter of 2003 will be granted Options or
SARs prior to the date of termination rather than after the end of the second
and fourth fiscal quarters, respectively, and as such will be granted unvested
Options or SARs subject to vesting at the end of the second fiscal quarter and
upon the achievement of the relevant performance goals in the fourth fiscal
quarter. Those Options and SARs will be prorated for the period of employment
during the first or second half of fiscal 2003, as applicable. Those prorated
Second Quarter Awards granted to terminating employees will vest and become
exercisable as to fifty percent (50%) of the underlying shares of Common Stock
on the date that Second Quarter Awards are granted to employees following the
second fiscal quarter and those prorated Fourth Quarter Awards granted to
terminating employees will vest and become exercisable as to twenty-five percent
(25%) of the underlying shares of Common Stock, subject to the achievement of
the Company's revenue and cash balance goals, on the date that Fourth Quarter
Awards are granted to employees following the fourth fiscal quarter. Prorated
Options and SARs granted to terminating employees will only be subject to
vesting as to fifty percent (50%) and twenty-five percent (25%), respectively,
and will expire three months after they vest.

     The Options and SARs will expire ten years from the date of grant, subject
to earlier expiration upon termination of employment with the Company and its
subsidiaries. The per share exercise price for the Options and SARs will be
equal to eighty percent (80%) of the market value of one share of Common Stock
on the effective date of the Retention Plan. There are currently no options or
stock appreciation rights outstanding having the same terms and conditions as
the Options and SARs to be granted pursuant to awards under the Retention Plan.

     The number and class of shares covered by each outstanding Option and SAR
and the exercise price per share thereof (but not the total price), and each
such Option and SAR, will all be proportionately adjusted for any increase or
decrease in the number of issued shares of Common Stock resulting from a
split-up or consolidation of shares or any like capital adjustment, or the
payment of any stock dividend.

     Except as provided below, upon a merger (other than a merger of the Company
in which the holders of Common Stock immediately prior to the merger have the
same proportionate ownership of common stock in the surviving corporation
immediately after the merger), consolidation, acquisition of property or stock,
separation, reorganization (other than a mere reincorporation or the creation of
a holding company) or liquidation of the Company, as a result of which the
shareholders of the Company receive cash, stock or other property in exchange
for or in connection with their shares of Common Stock, each Option and SAR will
terminate. Notwithstanding the foregoing, the optionee and SAR holder shall have
the right immediately prior to any such merger, consolidation, acquisition of
property or stock, separation, reorganization or liquidation


<PAGE>


to exercise such Option and SAR in whole or in part, to the extent the vesting
requirements have been satisfied.

     If the shareholders of the Company receive capital stock of another
corporation ("Exchange Stock") in exchange for their shares of Common Stock in
any transaction involving a merger (other than a merger of the Company in which
the holders of Common Stock immediately prior to the merger have the same
proportionate ownership of common stock in the surviving corporation immediately
after the merger), consolidation, acquisition of property or stock, separation
or reorganization (other than a mere reincorporation or the creation of a
holding company), all Options and SARs will be converted into options to
purchase and stock appreciation rights relating to shares of Exchange Stock
unless the Company and the corporation issuing the Exchange Stock, in their sole
discretion, determine that any or all such Options and SARs will not be
converted into options to purchase or stock appreciation rights relating to
shares of Exchange Stock, but instead will terminate in accordance with the
provisions set forth above. The amount and price of converted Options and SARs
subject to an award shall be determined by adjusting the amount and price of the
Options and SARs in the same proportion as used for determining the number of
shares of Exchange Stock the holders of the Common Stock receive in such merger,
consolidation, acquisition of property or stock, separation or reorganization.
Unless accelerated by the Board, the vesting schedule for the Options and SARs
will continue to apply for the Exchange Stock.

Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL

     Inapplicable

Item 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS

     The Company is a Delaware corporation. In its Certificate of Incorporation,
the Company has adopted the provisions of Section 102(b)(7) of the Delaware
General Corporation Law (the "Delaware Law"), which enables a corporation in its
original certificate of incorporation or an amendment thereto to eliminate or
limit the personal liability of a director for monetary damages for breach of
the director's fiduciary duty, except (i) for any breach of the director's duty
of loyalty to the corporation or its stockholders, (ii) for acts or omissions
not in good faith or which involve intentional misconduct or a knowing violation
of law, (iii) pursuant to Section 174 of the Delaware Law (providing for
liability of directors for unlawful payment of dividends or unlawful stock
purchases or redemptions) or (iv) for any transaction from which a director will
personally receive a benefit in money, property or services to which the
director is not legally entitled.

     The Company has also adopted indemnification provisions pursuant to Section
145 of the Delaware Law, which provides that a corporation may indemnify any
persons, including officers and directors, who are, or are threatened to be
made, parties to any threatened, pending or completed legal action, suit or
proceedings, whether civil, criminal, administrative or investigative (other
than an action by or in the right of the corporation), by reason of the fact
that such person was an officer, director, employee or agent of the corporation,
or is or was serving at the request of such corporation as a director, officer,
employee or agent of another corporation or enterprise. The indemnity may
include expenses (including attorney's fees), judgments, fines and amounts paid
in settlement actually and reasonably incurred by such person in connection


<PAGE>


with such action, suit or proceeding, provided such officer, director, employee
or agent acted in good faith and in a manner he reasonably believed to be in or
not opposed to the corporation's best interests and, with respect to criminal
proceedings, had no reasonable cause to believe that his conduct was unlawful. A
Delaware corporation may indemnify officers or directors in an action by or in
the right of the corporation under the same conditions, except that no
indemnification is permitted without judicial approval if the officer or
director is adjudged to be liable to the corporation. Where an officer or
director is successful on the merits or otherwise in the defense of any action
referred to above, the corporation must indemnify him against expenses
(including attorney's fees) that such officer or director actually and
reasonably incurred.

     XO Management Services, Inc., a subsidiary of the Company, entered into
indemnification agreements with certain officers and former directors of the
Company on July 14, 2002 to indemnify them for claims against them arising from
their employment by the Company, and for payment of related costs and expenses.

Item 7. EXEMPTION FROM REGISTRATION CLAIMED

     Inapplicable

Item 8. EXHIBITS

Exhibit No.
-----------

   5        Opinion of Willkie Farr & Gallagher with respect to the legality
            of the securities to be issued pursuant to the Plan.

   23.1     Consent of Ernst & Young LLP.

   23.2     Consent of Willkie Farr & Gallagher (contained in Exhibit 5).

Item 9. UNDERTAKINGS

     1. The undersigned registrant hereby undertakes:

          (a) To file, during any period in which offers or sales are being
     made, a post-effective amendment to the Registration Statement:

               (i) to include any prospectus required by Section 10(a)(3) of the
          Securities Act;

               (ii) to reflect in the prospectus any facts or events arising
          after the effective date of the Registration Statement (or the most
          recent post-effective amendment thereof) which, individually or in the
          aggregate, represent a fundamental change in the information set forth
          in the Registration Statement;


<PAGE>


               (iii) to include any material information with respect to the
          plan of distribution not previously disclosed in the Registration
          Statement or any material change to such information in the
          Registration Statement;

provided, however, that paragraphs (a)(i) and (a)(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 by the Company pursuant to
Section 13 or Section 15(d) of the Exchange Act that are incorporated by
reference in the Registration Statement.


<PAGE>


          (b) That, for the purpose of determining any liability under the
     Securities Act, 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.

          (c) 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.

     2. The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the Company's
annual report pursuant to Section 13(a) or 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.

     3. Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Company pursuant to the foregoing provisions, or otherwise, the Company has been
advised that in the opinion of the 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 Company of expenses incurred or paid
by a director, officer or controlling person of the Company in the successful
defense of any action, suit or proceeding) is asserted by such director, officer
or controlling person in connection with the securities being registered, the
Company 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.

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act, the Company certifies
that it has reasonable grounds to believe that it meets all of the requirements
for filing on Form S-8 and has duly caused this Registration Statement to be
signed on its behalf by the undersigned, thereunto duly authorized, in the City
of Reston, Commonwealth of Virginia, on the 19th day of June, 2003.

                                    XO Communications, Inc.

                                    By:  /s/ Wayne M. Rehberger
                                         ----------------------------------
                                         Wayne M. Rehberger
                                         Executive Vice President and Chief
                                         Financial Officer


<PAGE>


     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.

             Signature                         Title                      Date
             ---------                         -----                      ----

/s/ Carl J. Grivner                President, Chief                June 19, 2003
----------------------             Executive Officer
Carl J. Grivner                    and Director
                                   (Principal Executive
                                   Officer)


/s/ Wayne M. Rehberger             Executive Vice                  June 19, 2003
----------------------             President and Chief
Wayne M. Rehberger                 Financial Officer
                                   (Principal Financial
                                   Officer and
                                   Principal Accounting
                                   Officer)


<PAGE>


                                   Director                        June __, 2003
----------------------
Carl C. Icahn


/s/ Vincent Intrieri               Director                        June 18, 2003
----------------------
Vincent Intrieri


/s/ Keith Meister                  Director                        June 18, 2003
----------------------
Keith Meister


/s/ Adam Dell                      Director                        June 19 2003
----------------------
Adam Dell


/s/ Andrew R. Cohen                Director                        June 18, 2003
----------------------
Andrew R. Cohen


<PAGE>


                                INDEX TO EXHIBITS

Exhibit No.            Description of Exhibit
-----------            ----------------------

5           Opinion of Willkie Farr & Gallagher.

23.1        Consent of Ernst & Young LLP.

23.2        Consent of Willkie Farr & Gallagher (contained in
            Exhibit 5).
[{"type": "S-8", "sequence": "1", "filename": "xi1213486b.txt", "description": "REGISTRATION STATEMENT ON FORM S-8", "secsgml_size_bytes": 22657}]
{"company-data": {"conformed-name": "XO COMMUNICATIONS INC", "cik": "0001111634", "assigned-sic": "4813", "irs-number": "541983517", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-106302", "film-number": "03751069"}, "business-address": {"street1": "11111 SUNSNET HILLS ROAD", "city": "RESTON", "state": "VA", "zip": "22102", "phone": "7035472000"}, "mail-address": {"street1": "11111 SUNSET HILLS ROAD", "city": "RESTON", "state": "VA", "zip": "20190"}, "former-company": [{"former-conformed-name": "NEXTLINK COMMUNICATIONS INC/NEW", "date-changed": "20000622"}, {"former-conformed-name": "NM ACQUISITION CORP", "date-changed": "20000411"}]}
As filed with the Securities and Exchange Commission on June 20, 2003
                                                      Registration No. 333-_____
===============================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                        UNDER THE SECURITIES ACT OF 1933

                             XO COMMUNICATIONS, INC.
             (Exact name of registrant as specified in its charter)

           Delaware                                            54-1983517
  (State or other jurisdiction                              (I.R.S. Employer
of incorporation or organization)                       Identification Number)

                             11111 Sunset Hills Road
                             Reston, Virginia 20190
          (Address, including zip code, of principal executive offices)

                ------------------------------------------------
                             XO Communications, Inc.
                            2002 Stock Incentive Plan
                            (Full title of the plan)
                ------------------------------------------------

                               Wayne M. Rehberger
                Executive Vice President, Chief Financial Officer
                             XO Communications, Inc.
                             11111 Sunset Hills Road
                             Reston, Virginia 20190
                                 (703) 547-2000

    (Name, address, including zip code, and telephone number, including area
                           code, of agent for service)

                ------------------------------------------------
                                    Copies to
                              Bruce R. Kraus, Esq.
                            Willkie Farr & Gallagher
                               787 Seventh Avenue
                               New York, NY 10019
                                 (212) 728-8000
                ------------------------------------------------

                         CALCULATION OF REGISTRATION FEE

================================================================================
    Title of       Amount to be       Proposed        Proposed       Amount of
securities to be  registered (1)      maximum         maximum      registration
   registered                      offering price    aggregate          fee
                                        per           offering
                                     Option (2)      price (2)
--------------------------------------------------------------------------------
Options to
purchase and Stock
Appreciation
Rights relating
to Common
Stock, $0.01 par     1,900,000          N/A        $10,708,067.00     $866.28
value per share
===============================================================================

     (1) This Registration Statement covers the offer and sale of options to
purchase ("Options") and stock appreciation rights relating to ("SARs") an
aggregate of 1,900,000 shares of the common stock of XO Communications, Inc.,
$0.01 par value per share, issuable pursuant to the XO Communications, Inc. 2002
Stock Incentive Plan (the "Plan") through awards granted under the XO
Communications, Inc. 2003 Employee Retention and Incentive Plan (the "Retention
Plan"). In addition, this Registration Statement covers an indeterminable number
of additional Options and SARs as may hereafter be offered or issued pursuant to
the Plan, to prevent dilution resulting from stock splits, stock dividends or
similar transactions effected without receipt of consideration and pursuant to
Rule 416(c) under the Securities Act of 1933, as amended (the "Securities Act").

     (2) Estimated solely for calculating the amount of the registration fee.
The registration fee has been calculated based on the aggregate potential cash
awards that the Option and SAR recipients may elect to waive in order to have
the opportunity to earn Option and SAR awards under the Retention Plan.
PART II

                           INFORMATION REQUIRED IN THE
                             REGISTRATION STATEMENT

Item 3. INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

     The following documents, filed with the Securities and Exchange Commission
(the "Commission") by XO Communications, Inc., a Delaware corporation (the
"Company"), are incorporated by reference into this Registration Statement:

          (a) the Company's Annual Report on Form 10-K for the fiscal year ended
     December 31, 2002, filed pursuant to the Securities Exchange Act of 1934
     (the "Exchange Act");

          (b) the Company's Quarterly Report on Form 10-Q for the quarter ended
     March 31, 2003, filed pursuant to the Exchange Act; and

          (c) the Company's Current Reports on Form 8-K, filed on May 19, 2003,
     June 6, 2003 and June 13, 2003 pursuant to the Exchange Act;

     In addition, all documents filed by the Company with the Commission
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent
to the date of the Registration Statement and prior to the filing of a
post-effective amendment which indicates that all the securities offered hereby
have been sold or which deregisters all securities then remaining unsold shall
be deemed to be incorporated herein by reference and to be a part hereof from
the date of the filing of such documents with the Commission.

     THE COMPANY WILL PROVIDE WITHOUT CHARGE, UPON WRITTEN OR ORAL REQUEST, A
COPY OF ANY OR ALL OF THE FOREGOING DOCUMENTS INCORPORATED HEREIN BY REFERENCE
(OTHER THAN EXHIBITS TO SUCH DOCUMENTS). IN ADDITION, THE COMPANY WILL PROVIDE
ALL DOCUMENTS REQUIRED TO BE DELIVERED TO PARTICIPANTS PURSUANT TO RULE 428(b)
OF THE SECURITIES ACT. REQUESTS FOR SUCH DOCUMENTS SHOULD BE DIRECTED TO GENERAL
COUNSEL, XO COMMUNICATIONS, INC., 11111 SUNSET HILLS ROAD, RESTON, VIRGINIA
20190, (703) 547-2000.

Item 4. DESCRIPTION OF SECURITIES

     The Options are options to purchase shares of the Company's common stock,
$0.01 par value per share (the "Common Stock"), to be issued pursuant to the
Company's 2002 Stock Incentive Plan as a result of awards granted under the
Company's 2003 Employee Retention and Incentive Plan (the "Retention Plan"). A
SAR gives the recipient the right to exercise the SAR and receive a cash amount
equal to the excess of the fair market value of one share of Common Stock on the
date of exercise over the exercise price stated in the SAR multiplied by the
number of shares with respect to which the SAR is being exercised. Options and
SARs covering an aggregate of 1,900,000 shares of Common Stock have been
authorized for issuance by the Company. Pursuant to the terms of the Retention
Plan, except as set forth below for Options and SARs granted to terminating
employees, Options and SARs will be granted (i) upon the completion of the
Company's second fiscal quarter of 2003 (the "Second Quarter Awards") and (ii)
upon the attainment of certain year-end Company revenue and cash balance goals
following the end of fiscal 2003 (the "Fourth Quarter
Awards"). The Second Quarter Awards will be fifty percent (50%) vested and
exercisable on the date of grant, with the remaining fifty percent (50%) vesting
ratably every month for twenty four (24) months following the month of grant.
The Fourth Quarter Awards will be twenty-five percent (25%) vested and
exercisable on the date of grant, with the remaining seventy-five percent (75%)
vesting ratably every month for thirty-six (36) months following the month of
grant. Vesting of the Options and SARs is subject to continued employment with
the Company or a subsidiary on the respective vesting dates.

     Participants in the Retention Plan who terminate employment with the
Company and its subsidiaries prior to the end of either the second fiscal
quarter of 2003 or the fourth fiscal quarter of 2003 will be granted Options or
SARs prior to the date of termination rather than after the end of the second
and fourth fiscal quarters, respectively, and as such will be granted unvested
Options or SARs subject to vesting at the end of the second fiscal quarter and
upon the achievement of the relevant performance goals in the fourth fiscal
quarter. Those Options and SARs will be prorated for the period of employment
during the first or second half of fiscal 2003, as applicable. Those prorated
Second Quarter Awards granted to terminating employees will vest and become
exercisable as to fifty percent (50%) of the underlying shares of Common Stock
on the date that Second Quarter Awards are granted to employees following the
second fiscal quarter and those prorated Fourth Quarter Awards granted to
terminating employees will vest and become exercisable as to twenty-five percent
(25%) of the underlying shares of Common Stock, subject to the achievement of
the Company's revenue and cash balance goals, on the date that Fourth Quarter
Awards are granted to employees following the fourth fiscal quarter. Prorated
Options and SARs granted to terminating employees will only be subject to
vesting as to fifty percent (50%) and twenty-five percent (25%), respectively,
and will expire three months after they vest.

     The Options and SARs will expire ten years from the date of grant, subject
to earlier expiration upon termination of employment with the Company and its
subsidiaries. The per share exercise price for the Options and SARs will be
equal to eighty percent (80%) of the market value of one share of Common Stock
on the effective date of the Retention Plan. There are currently no options or
stock appreciation rights outstanding having the same terms and conditions as
the Options and SARs to be granted pursuant to awards under the Retention Plan.

     The number and class of shares covered by each outstanding Option and SAR
and the exercise price per share thereof (but not the total price), and each
such Option and SAR, will all be proportionately adjusted for any increase or
decrease in the number of issued shares of Common Stock resulting from a
split-up or consolidation of shares or any like capital adjustment, or the
payment of any stock dividend.

     Except as provided below, upon a merger (other than a merger of the Company
in which the holders of Common Stock immediately prior to the merger have the
same proportionate ownership of common stock in the surviving corporation
immediately after the merger), consolidation, acquisition of property or stock,
separation, reorganization (other than a mere reincorporation or the creation of
a holding company) or liquidation of the Company, as a result of which the
shareholders of the Company receive cash, stock or other property in exchange
for or in connection with their shares of Common Stock, each Option and SAR will
terminate. Notwithstanding the foregoing, the optionee and SAR holder shall have
the right immediately prior to any such merger, consolidation, acquisition of
property or stock, separation, reorganization or liquidation
to exercise such Option and SAR in whole or in part, to the extent the vesting
requirements have been satisfied.

     If the shareholders of the Company receive capital stock of another
corporation ("Exchange Stock") in exchange for their shares of Common Stock in
any transaction involving a merger (other than a merger of the Company in which
the holders of Common Stock immediately prior to the merger have the same
proportionate ownership of common stock in the surviving corporation immediately
after the merger), consolidation, acquisition of property or stock, separation
or reorganization (other than a mere reincorporation or the creation of a
holding company), all Options and SARs will be converted into options to
purchase and stock appreciation rights relating to shares of Exchange Stock
unless the Company and the corporation issuing the Exchange Stock, in their sole
discretion, determine that any or all such Options and SARs will not be
converted into options to purchase or stock appreciation rights relating to
shares of Exchange Stock, but instead will terminate in accordance with the
provisions set forth above. The amount and price of converted Options and SARs
subject to an award shall be determined by adjusting the amount and price of the
Options and SARs in the same proportion as used for determining the number of
shares of Exchange Stock the holders of the Common Stock receive in such merger,
consolidation, acquisition of property or stock, separation or reorganization.
Unless accelerated by the Board, the vesting schedule for the Options and SARs
will continue to apply for the Exchange Stock.

Item 5. INTERESTS OF NAMED EXPERTS AND COUNSEL

     Inapplicable

Item 6. INDEMNIFICATION OF DIRECTORS AND OFFICERS

     The Company is a Delaware corporation. In its Certificate of Incorporation,
the Company has adopted the provisions of Section 102(b)(7) of the Delaware
General Corporation Law (the "Delaware Law"), which enables a corporation in its
original certificate of incorporation or an amendment thereto to eliminate or
limit the personal liability of a director for monetary damages for breach of
the director's fiduciary duty, except (i) for any breach of the director's duty
of loyalty to the corporation or its stockholders, (ii) for acts or omissions
not in good faith or which involve intentional misconduct or a knowing violation
of law, (iii) pursuant to Section 174 of the Delaware Law (providing for
liability of directors for unlawful payment of dividends or unlawful stock
purchases or redemptions) or (iv) for any transaction from which a director will
personally receive a benefit in money, property or services to which the
director is not legally entitled.

     The Company has also adopted indemnification provisions pursuant to Section
145 of the Delaware Law, which provides that a corporation may indemnify any
persons, including officers and directors, who are, or are threatened to be
made, parties to any threatened, pending or completed legal action, suit or
proceedings, whether civil, criminal, administrative or investigative (other
than an action by or in the right of the corporation), by reason of the fact
that such person was an officer, director, employee or agent of the corporation,
or is or was serving at the request of such corporation as a director, officer,
employee or agent of another corporation or enterprise. The indemnity may
include expenses (including attorney's fees), judgments, fines and amounts paid
in settlement actually and reasonably incurred by such person in connection
with such action, suit or proceeding, provided such officer, director, employee
or agent acted in good faith and in a manner he reasonably believed to be in or
not opposed to the corporation's best interests and, with respect to criminal
proceedings, had no reasonable cause to believe that his conduct was unlawful. A
Delaware corporation may indemnify officers or directors in an action by or in
the right of the corporation under the same conditions, except that no
indemnification is permitted without judicial approval if the officer or
director is adjudged to be liable to the corporation. Where an officer or
director is successful on the merits or otherwise in the defense of any action
referred to above, the corporation must indemnify him against expenses
(including attorney's fees) that such officer or director actually and
reasonably incurred.

     XO Management Services, Inc., a subsidiary of the Company, entered into
indemnification agreements with certain officers and former directors of the
Company on July 14, 2002 to indemnify them for claims against them arising from
their employment by the Company, and for payment of related costs and expenses.

Item 7. EXEMPTION FROM REGISTRATION CLAIMED

     Inapplicable

Item 8. EXHIBITS

Exhibit No.
-----------

   5        Opinion of Willkie Farr & Gallagher with respect to the legality
            of the securities to be issued pursuant to the Plan.

   23.1     Consent of Ernst & Young LLP.

   23.2     Consent of Willkie Farr & Gallagher (contained in Exhibit 5).

Item 9. UNDERTAKINGS

     1. The undersigned registrant hereby undertakes:

          (a) To file, during any period in which offers or sales are being
     made, a post-effective amendment to the Registration Statement:

               (i) to include any prospectus required by Section 10(a)(3) of the
          Securities Act;

               (ii) to reflect in the prospectus any facts or events arising
          after the effective date of the Registration Statement (or the most
          recent post-effective amendment thereof) which, individually or in the
          aggregate, represent a fundamental change in the information set forth
          in the Registration Statement;
(iii) to include any material information with respect to the
          plan of distribution not previously disclosed in the Registration
          Statement or any material change to such information in the
          Registration Statement;

provided, however, that paragraphs (a)(i) and (a)(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 by the Company pursuant to
Section 13 or Section 15(d) of the Exchange Act that are incorporated by
reference in the Registration Statement.
(b) That, for the purpose of determining any liability under the
     Securities Act, 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.

          (c) 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.

     2. The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the Company's
annual report pursuant to Section 13(a) or 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.

     3. Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Company pursuant to the foregoing provisions, or otherwise, the Company has been
advised that in the opinion of the 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 Company of expenses incurred or paid
by a director, officer or controlling person of the Company in the successful
defense of any action, suit or proceeding) is asserted by such director, officer
or controlling person in connection with the securities being registered, the
Company 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.

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act, the Company certifies
that it has reasonable grounds to believe that it meets all of the requirements
for filing on Form S-8 and has duly caused this Registration Statement to be
signed on its behalf by the undersigned, thereunto duly authorized, in the City
of Reston, Commonwealth of Virginia, on the 19th day of June, 2003.

                                    XO Communications, Inc.

                                    By:  /s/ Wayne M. Rehberger
                                         ----------------------------------
                                         Wayne M. Rehberger
                                         Executive Vice President and Chief
                                         Financial Officer
Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.

             Signature                         Title                      Date
             ---------                         -----                      ----

/s/ Carl J. Grivner                President, Chief                June 19, 2003
----------------------             Executive Officer
Carl J. Grivner                    and Director
                                   (Principal Executive
                                   Officer)

/s/ Wayne M. Rehberger             Executive Vice                  June 19, 2003
----------------------             President and Chief
Wayne M. Rehberger                 Financial Officer
                                   (Principal Financial
                                   Officer and
                                   Principal Accounting
                                   Officer)
Director                        June __, 2003
----------------------
Carl C. Icahn

/s/ Vincent Intrieri               Director                        June 18, 2003
----------------------
Vincent Intrieri

/s/ Keith Meister                  Director                        June 18, 2003
----------------------
Keith Meister

/s/ Adam Dell                      Director                        June 19 2003
----------------------
Adam Dell

/s/ Andrew R. Cohen                Director                        June 18, 2003
----------------------
Andrew R. Cohen
INDEX TO EXHIBITS

Exhibit No.            Description of Exhibit
-----------            ----------------------

5           Opinion of Willkie Farr & Gallagher.

23.1        Consent of Ernst & Young LLP.

23.2        Consent of Willkie Farr & Gallagher (contained in
            Exhibit 5).