UNITED STATES SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 10-Q/A

        [X]     QUARTERLY  REPORT  PURSUANT  TO  SECTION  13  OR  15(d)  OF  THE
                SECURITIES EXCHANGE ACT OF 1934

                For the Quarterly Period Ended September 30, 2003

                                       OR

        [ ]     TRANSITION  REPORT  PURSUANT  TO  SECTION  13 OR 15(d) OF THE
                SECURITIES EXCHANGE ACT OF 1934

<TABLE>
<CAPTION>

     Commission                 Name of Registrant; State of Incorporation;                  IRS Employer
     File Number                Address of Principal Executive Offices; and                  Identification
                                Telephone Number                                             Number
---------------------      ---------------------------------------------------------    ------------------------
<S>  <C>                                                                                     <C>
     1-16169                    EXELON CORPORATION                                           23-2990190
                                (a Pennsylvania corporation)
                                10 South Dearborn Street - 37th Floor
                                P.O. Box 805379
                                Chicago, Illinois 60680-5379
                                (312) 394-7398
     1-1839                     COMMONWEALTH EDISON COMPANY                                  36-0938600
                                (an Illinois corporation)
                                10 South Dearborn Street - 37th Floor
                                P.O. Box 805379
                                Chicago, Illinois 60680-5379
                                (312) 394-4321
     1-1401                     PECO ENERGY COMPANY                                          23-0970240
                                (a Pennsylvania corporation)
                                P.O. Box 8699 2301 Market Street
                                Philadelphia, Pennsylvania 19101-8699
                                (215) 841-4000
     333-85496                  EXELON GENERATION COMPANY, LLC                               23-3064219
                                (a Pennsylvania limited liability company)
                                300 Exelon Way
                                Kennett Square, Pennsylvania 19348
                                (610) 765-6900
</TABLE>

      Indicate by check mark  whether the  registrant  (1) has filed all reports
required to be filed by Section 13 or 15(d) of the  Securities  Exchange  Act of
1934  during  the  preceding  12 months  (or for such  shorter  period  that the
registrant was required to file such reports),  and (2) has been subject to such
filing requirements for the past 90 days. Yes [X] No [_].

     The number of shares outstanding of each registrant's common stock as of
September 30, 2003 was:

     Exelon Corporation Common Stock, without par value              327,021,190
     Commonwealth Edison Company Common Stock, $12.50 par value      127,016,483
     PECO Energy Company Common Stock, without par value             170,478,507
     Exelon Generation Company, LLC                               not applicable

      Indicate by check mark whether the registrant is an accelerated  filer (as
defined  in  Rule  12b-2  of  the  Act).  Exelon  Corporation  Yes  [X]  No  [ ]
Commonwealth Edison Company,  PECO Energy Company and Exelon Generation Company,
LLC Yes [ ] No [X].


<PAGE>



                                TABLE OF CONTENTS


                                                                      Page No.
                                                                      --------
      FILING FORMAT                                                      3
      EXPLANATORY NOTE                                                   3

      PART I.   FINANCIAL INFORMATION                                    4
      ITEM 4.   CONTROLS AND PROCEDURES                                  4
      PART II.  OTHER INFORMATION                                        7
      ITEM 6.   EXHIBITS AND REPORTS ON FORM 8-K                         7

      SIGNATURES                                                        10







                                       2
<PAGE>

      FILING FORMAT
      This combined Form 10-Q/A is being filed separately by Exelon  Corporation
(Exelon),  Commonwealth  Edison Company (ComEd),  PECO Energy Company (PECO) and
Exelon Generation Company, LLC (Generation) (Registrants). Information contained
herein  relating to any individual  registrant has been filed by such registrant
on its own behalf.  No registrant  makes any  representation  as to  information
relating to any other registrant.

      EXPLANATORY NOTE
      Exelon,  ComEd, PECO and Generation are filing this amendment on Form 10-Q
/A in  response  to  comments  received  from the  staff of the  Securities  and
Exchange Commission (SEC) in connection with its review of Exelon's Registration
Statement on Form S-3 (File No. 333-108546).

      This amendment makes changes to Part I, Item 4. Controls and Procedures to
clarify  that each  Registrant's  access  and  ability  to apply its  disclosure
controls and  procedures to entities that it does not control or manage are more
limited than subsidiaries that it controls and manages.

      Unless otherwise stated, all information contained in this amendment is as
of October 29, 2003,  the filing date of our original  Quarterly  Report on Form
10-Q for the quarter ended September 30, 2003.






                                       3
<PAGE>

     PART I.          FINANCIAL INFORMATION
     ITEM 4.          CONTROLS AND PROCEDURES

      Exelon

      During  the third  quarter of 2003,  Exelon's  management,  including  the
principal executive officer and principal financial officer,  evaluated Exelon's
disclosure  controls  and  procedures  related  to  the  recording,  processing,
summarization  and reporting of information in Exelon's periodic reports that it
files with the SEC. These disclosure  controls and procedures have been designed
to ensure  that (a)  material  information  relating  to Exelon,  including  its
consolidated subsidiaries, is made known to Exelon's management, including these
officers,  by other  employees  of  Exelon  and its  subsidiaries,  and (b) this
information  is recorded,  processed,  summarized,  evaluated and  reported,  as
applicable,  within the time periods specified in the SEC's rules and forms. Due
to the inherent  limitations of control systems,  not all  misstatements  may be
detected.  These  inherent  limitations  include the realities that judgments in
decision-making  can be faulty and that  breakdowns  can occur because of simple
error or mistake. Additionally, controls could be circumvented by the individual
acts of some persons or by collusion  of two or more people.  Exelon's  controls
and procedures  can only provide  reasonable,  not absolute,  assurance that the
above objectives have been met. Exelon does not control or manage certain of its
unconsolidated  entities and thus its access and ability to apply its disclosure
controls and  procedures to entities that it does not control or manage are more
limited than is the case for the subsidiaries it controls and manages.

      Accordingly, as of September 30, 2003, these officers (principal executive
officer and principal  financial  officer)  concluded  that Exelon's  disclosure
controls and procedures were effective to accomplish  their  objectives.  Exelon
continually strives to improve its disclosure controls and procedures to enhance
the quality of its  financial  reporting  and to maintain  dynamic  systems that
change as conditions warrant.

      ComEd

      During  the third  quarter  of 2003,  ComEd's  management,  including  the
principal executive officer and principal  financial officer,  evaluated ComEd's
disclosure  controls  and  procedures  related  to  the  recording,  processing,
summarization  and reporting of information in ComEd's  periodic reports that it
files with the SEC. These disclosure  controls and procedures have been designed
to  ensure  that (a)  material  information  relating  to ComEd,  including  its
consolidated subsidiaries, is made known to ComEd's management,  including these
officers,  by  other  employees  of  ComEd  and its  subsidiaries,  and (b) this
information  is recorded,  processed,  summarized,  evaluated and  reported,  as
applicable,  within the time periods specified in the SEC's rules and forms. Due
to the inherent  limitations of control systems,  not all  misstatements  may be
detected.  These  inherent  limitations  include the realities that judgments in
decision-making  can be faulty and that  breakdowns  can occur because of simple
error or mistake. Additionally, controls could be circumvented by the individual
acts of some persons or by collusion of two or more people. ComEd's controls and
procedures can only provide reasonable,  not absolute,  assurance that the above
objectives  have been met.  ComEd  does not  control  or manage  certain  of its
unconsolidated  entities and thus its access and ability to apply its disclosure



                                       4
<PAGE>

controls and  procedures to entities that it does not control or manage are more
limited than is the case for the subsidiaries it controls and manages.

      Accordingly, as of September 30, 2003, these officers (principal executive
officer and  principal  financial  officer)  concluded  that ComEd's  disclosure
controls and procedures  were effective to accomplish  their  objectives.  ComEd
continually strives to improve its disclosure controls and procedures to enhance
the quality of its  financial  reporting  and to maintain  dynamic  systems that
change as conditions warrant.

      PECO
      During  the  third  quarter  of 2003,  PECO's  management,  including  the
principal  executive officer and principal  financial officer,  evaluated PECO's
disclosure  controls  and  procedures  related  to  the  recording,  processing,
summarization  and reporting of information in PECO's  periodic  reports that it
files with the SEC. These disclosure  controls and procedures have been designed
to  ensure  that  (a)  material  information  relating  to PECO,  including  its
consolidated subsidiaries,  is made known to PECO's management,  including these
officers,  by  other  employees  of PECO  and  its  subsidiaries,  and (b)  this
information  is recorded,  processed,  summarized,  evaluated and  reported,  as
applicable,  within the time periods specified in the SEC's rules and forms. Due
to the inherent  limitations of control systems,  not all  misstatements  may be
detected.  These  inherent  limitations  include the realities that judgments in
decision-making  can be faulty and that  breakdowns  can occur because of simple
error or mistake. Additionally, controls could be circumvented by the individual
acts of some persons or by collusion of two or more people.  PECO's controls and
procedures can only provide reasonable,  not absolute,  assurance that the above
objectives  have  been met.  PECO does not  control  or  manage  certain  of its
unconsolidated  entities and thus its access and ability to apply its disclosure
controls and  procedures to entities that it does not control or manage are more
limited than is the case for the subsidiaries it controls and manages.

      Accordingly, as of September 30, 2003, these officers (principal executive
officer and  principal  financial  officer)  concluded  that  PECO's  disclosure
controls and procedures  were  effective to accomplish  their  objectives.  PECO
continually strives to improve its disclosure controls and procedures to enhance
the quality of its  financial  reporting  and to maintain  dynamic  systems that
change as conditions warrant.

      Generation

      During the third quarter of 2003, Generation's  management,  including the
principal   executive  officer  and  principal   financial  officer,   evaluated
Generation's  disclosure  controls  and  procedures  related  to the  recording,
processing,  summarization and reporting of information in Generation's periodic
reports that it files with the SEC.  These  disclosure  controls and  procedures
have  been  designed  to  ensure  that  (a)  material  information  relating  to
Generation,   including  its  consolidated   subsidiaries,   is  made  known  to
Generation's  management,  including  these  officers,  by  other  employees  of
Generation  and  its  subsidiaries,   and  (b)  this  information  is  recorded,
processed,  summarized,  evaluated and reported, as applicable,  within the time
periods specified in the SEC's rules and forms. Due to the inherent  limitations
of control  systems,  not all  misstatements  may be  detected.  These  inherent
limitations  include the  realities  that  judgments in  decision-making  can be
faulty  and that  breakdowns  can  occur  because  of simple  error or



                                       5
<PAGE>


mistake. Additionally,  controls could be circumvented by the individual acts of
some persons or by collusion  of two or more people.  Generation's  controls and
procedures can only provide reasonable,  not absolute,  assurance that the above
objectives  have been met.  Generation does not control or manage certain of its
unconsolidated  entities and thus its access and ability to apply its disclosure
controls and  procedures to entities that it does not control or manage are more
limited than is the case for the subsidiaries it controls and manages.

      Accordingly, as of September 30, 2003, these officers (principal executive
officer and principal financial officer) concluded that Generation's  disclosure
controls  and  procedures  were  effective  to  accomplish   their   objectives.
Generation continually strives to improve its disclosure controls and procedures
to enhance  the  quality of its  financial  reporting  and to  maintain  dynamic
systems that change as conditions warrant.





                                       6
<PAGE>



PART II. OTHER INFORMATION
ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K

     (a) Exhibits:

        10-1 -  Retirement  and  Separation  between  Exelon  Corporation,  PECO
                Energy  Company  and  Kenneth G.  Lawrence,  dated as of May 11,
                2003. Filed on behalf of PECO.*

        10-2 -  Purchase  and  Sale  Agreement  dated as  of  October  10,  2003
                between  British Energy  Investment  Ltd. and Exelon  Generation
                Company,  LLC  relating to the sale and  purchase of 100% of the
                shares of British  Energy US  Holdings  Inc.  Filed on behalf of
                Exelon and Generation.*
     ---------------------------------------------------------------------------
     Certifications  Pursuant to Rule  13a-14(a) and 15d-14(a) of the Securities
     and  Exchange Act of 1934 as to the Quarterly Report on Form 10-Q/A for the
     quarterly  period ended September 30, 2003 filed by the following  officers
     for the following companies:
     ---------------------------------------------------------------------------

     31-1  -  Filed by John W. Rowe for Exelon Corporation
     31-2  -  Filed by Robert S. Shapard for Exelon Corporation
     31-3  -  Filed by Michael B. Bemis for Commonwealth Edison Company
     31-4  -  Filed by J. Barry Mitchell for Commonwealth Edison Company
     31-5  -  Filed by Michael B. Bemis for PECO Energy Company
     31-6  -  Filed by J. Barry Mitchell for PECO Energy Company
     31-7  -  Filed by Oliver D. Kingsley Jr. for Exelon Generation Company, LLC
     31-8  -  Filed by J. Barry Mitchell for Exelon Generation Company, LLC
     ---------------------------------------------------------------------------

     Certifications  Pursuant  to Section  1350 of Chapter 63 of Title 18 United
     States Code  (Sarbanes - Oxley Act of 2002) as to the  Quarterly  Report on
     Form 10-Q for the  quarterly  period ended  September 30, 2003 filed by the
     following officers for the following companies:*
     ---------------------------------------------------------------------------

     32-1  -    Filed by John W. Rowe for Exelon Corporation
     32-2  -    Filed by Robert S. Shapard for Exelon Corporation
     32-3  -    Filed by Michael B. Bemis for Commonwealth Edison Company
     32-4  -    Filed by Robert S. Shapard for Commonwealth Edison Company
     32-5  -    Filed by Michael B. Bemis for PECO Energy Company
     32-6  -    Filed by Robert S. Shapard for PECO Energy Company
     32-7  -    Filed by Oliver D. Kingsley Jr. for Exelon Generation Company,
                LLC
     32-8  -    Filed by Robert S. Shapard for Exelon Generation Company, LLC
     ---------------------------------------------------------------------------

     * Exhibits  were filed with the Form 10-Q for the  quarterly  period  ended
     September 30, 2003 filed on October 29, 2003 (File No.  1-16169,  September
     30, 2003 Form 10-Q, Exhibits 10-1 through 32-8).




                                       7
<PAGE>


      (b)     Reports on Form 8-K:

      Exelon,  ComEd,  PECO and/or  Generation filed Current Reports on Form 8-K
during the three months ended September 30, 2003 regarding the following items:
<TABLE>
<CAPTION>

              Date of Earliest
              Event Reported            Description of Item Reported
------------------------------------------------------------------------------------------------------------
<S>                <C>                        <C>
              July 3, 2003              "ITEM 5. OTHER  EVENTS"  filed for Exelon and  Generation  regarding
                                        the fact that EBG did not anticipate  that the  construction  of the
                                        Mystic 8 and 9 and Fore  River  generating  stations  would  achieve
                                        Project  Completion as defined in EBG's credit  facility by July 11,
                                        2003.

              July 29, 2003             "ITEM 5. OTHER  EVENTS" filed for Exelon and  Generation  announcing
                                        that Exelon  commenced the process of an orderly  transition  out of
                                        the ownership of EBG and the projects.

              August 6, 2003            "ITEM 5. OTHER EVENTS" filed for Exelon,  ComEd, PECO and Generation
                                        reaffirming   Exelon's   2003  earnings   guidance  and   announcing
                                        workforce reductions related to The Exelon Way.

              August 13, 2003           "ITEM 5. OTHER EVENTS" filed for Exelon and  Generation  regarding a
                                        note to Exelon's  financial  community  announcing an agreement with
                                        entities  controlled  by  Reservoir  to  sell  50% of  Sithe,  after
                                        closing on a call  transaction  announced in May 2003. In a separate
                                        transaction,  Sithe has entered into an agreement  with  Resevoir to
                                        sell entities holding six U.S.  generating  facilities and an entity
                                        holding Sithe's Canadian assets.

              August 25, 2003           "ITEM 5. OTHER  EVENTS"  filed for ComEd  regarding  ComEd's sale of
                                        $250  million  of  First   Mortgage   Bonds.   "ITEM  7.   FINANCIAL
                                        STATEMENTS  AND  EXHIBITS"  including  exhibits to ComEd's Form S-3,
                                        Registration No. 333-99363.

              August 29, 2003           "ITEM 5. OTHER  EVENTS"  filed for Exelon and  Generation  regarding
                                        the fact that the period  during  which the lenders  were  precluded
                                        from  exercising any remedies  resulting from the failure of the EBG
                                        projects  to achieve  Project  Completion  had  expired.  Exelon was
                                        continuing  discussions  with  the  lenders  regarding  the  orderly
                                        transition  of the  projects.  Exelon has  informed the lenders that
                                        Generation  will not  provide  additional  funding  to the  projects
                                        beyond its existing contractual obligations.

              September 12, 2003        "ITEM 5. OTHER EVENTS" filed
                                        for Exelon and ComEd regarding a filing
                                        with the Federal Energy Regulatory
                                        Commission


                                       8
<PAGE>


                                        to seek an adjustment in transmission
                                        rates. The exhibit includes the press
                                        release announcing the filing.

              September 24, 2003        "ITEM 5. OTHER EVENTS" filed
                                        for Exelon announcing that it had
                                        finalized the sale of InfraSource, Inc.

              September 26, 2003        "ITEM 5. OTHER EVENTS" filed
                                        for Exelon and ComEd announcing that
                                        Exelon is exploring the possibility of
                                        acquiring Illinois Power Company from
                                        Dynegy Inc.
------------------------------------------------------------------------------------------------------------

</TABLE>



                                       9
<PAGE>


                                   SIGNATURES
--------------------------------------------------------------------------------

      Pursuant to  requirements  of the  Securities  Exchange  Act of 1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.

                               EXELON CORPORATION

  /s/ John W. Rowe                            /s/ Robert S. Shapard
  ----------------------------                ----------------------------------
  JOHN W. ROWE                                ROBERT S. SHAPARD
  Chairman and                                Executive Vice President and Chief
  Chief Executive Officer                     Financial Officer
  (Principal Executive Officer)               (Principal Financial Officer)

  /s/ Matthew F. Hilzinger
  ---------------------------------------
  MATTHEW F. HILZINGER
  Vice President and Corporate Controller
  (Principal Accounting Officer)

  December 15, 2003

--------------------------------------------------------------------------------

      Pursuant to  requirements  of the  Securities  Exchange  Act of 1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.

                           COMMONWEALTH EDISON COMPANY

     /s/ Michael B. Bemis                     /s/ J. Barry Mitchell
     ---------------------------------        -------------------------------
     MICHAEL B. BEMIS                         J. BARRY MITCHELL
     President, Exelon Energy Delivery        Chief Financial Officer
     (Principal Executive Officer)            (Principal Financial Officer)


     /s/ Duane M. DesParte                    /s/ Frank M. Clark
     ------------------------------           ------------------
     DUANE M. DESPARTE                        FRANK M. CLARK
     Vice President and Controller,           President, ComEd
     Exelon Energy Delivery
     (Principal Accounting Officer)

      December 15, 2003










                                       10
<PAGE>

--------------------------------------------------------------------------------

      Pursuant to  requirements  of the  Securities  Exchange  Act of 1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.

                                   PECO ENERGY COMPANY

     /s/ Michael B. Bemis                     /s/ J. Barry Mitchell
     ---------------------------------        -------------------------------
     MICHAEL B. BEMIS                         J. BARRY MITCHELL
     President, Exelon Energy Delivery        Chief Financial Officer
     (Principal Executive Officer)            (Principal Financial Officer)


     /s/ Duane M. DesParte                    /s/ Denis P. O'Brien
     ------------------------------           ---------------------
     DUANE M. DESPARTE                        DENIS P. O'BRIEN
     Vice President and Controller,           President, PECO
     Exelon Energy Delivery
     (Principal Accounting Officer)

      December 15, 2003

--------------------------------------------------------------------------------


      Pursuant to  requirements  of the  Securities  Exchange  Act of 1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.

                         EXELON GENERATION COMPANY, LLC

     /s/ Oliver D. Kingsley Jr.               /s/ J. Barry Mitchell
     -----------------------------            -------------------------------
     OLIVER D. KINGSLEY JR.                   J. BARRY MITCHELL
     Chief Executive Officer and              Chief Financial Officer
     President                                (Principal Financial Officer)
     (Principal Executive Officer)


     /s/ Matthew F. Hilzinger
     -----------------------------------------------
     MATTHEW F. HILZINGER
     Vice President and Corporate Controller, Exelon
     (Principal Accounting Officer)


      December 15, 2003



                                       11