SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549



                                    FORM 8-K


                                 CURRENT REPORT




     Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934



                Date of Report (Date of earliest event reported):
                                  May 30, 2003





                               AMEREN CORPORATION
             (Exact name of registrant as specified in its charter)




         Missouri                        1-14756                43-1723446
(State or other jurisdiction           (Commission           (I.R.S. Employer
      of incorporation)                File Number)          Identification No.)




                 1901 Chouteau Avenue, St. Louis, Missouri 63103
              (Address of principal executive offices and Zip Code)






       Registrant's telephone number, including area code: (314) 621-3222


ITEM 5. OTHER EVENTS AND REGULATION FD DISCLOSURE.

     Reference is made to "Regulatory  Matters" under  "Management's  Discussion
and Analysis of Financial Condition and Results of Operations" and "Intercompany
Transfer  of  Electric  Generating  Facilities"  under  Note 3 to the  "Notes to
Consolidated  Financial  Statements"  of the  Registrant's  Form  10-Q  for  the
quarterly period ended March 31, 2003, for a discussion of the proposed transfer
to the  Registrant's  subsidiary,  Union  Electric  Company,  which  operates as
AmerenUE,  of approximately 550 megawatts of combustion turbine generating units
at Pinckneyville  and Kinmundy,  Illinois from AmerenEnergy  Generating  Company
(Generating Company),  another subsidiary, and for a discussion of the status of
the related  proceedings  before the Illinois Commerce  Commission (ICC) and the
Federal Energy Regulatory Commission (FERC).

     On May 30,  2003,  AmerenUE  filed a  Notice  of  Withdrawal  with  the ICC
notifying it that AmerenUE had elected not to pursue approval of the transaction
and was  withdrawing  its  request.  In the  Notice,  AmerenUE  states  that the
concerns expressed by the ICC Staff regarding AmerenUE's means of satisfying its
generating   capacity  needs,   juxtaposed  with  the  Missouri  Public  Service
Commission's  (MoPSC)  views  of the  appropriate  means of  meeting  generating
capacity  obligations,  have demonstrated to AmerenUE the difficulty of a single
company  operating  as an  electric  utility  in  both  a  regulated  generation
jurisdiction such as Missouri and an unregulated generation jurisdiction such as
Illinois.  To remedy this difficulty,  AmerenUE announced in the Notice its plan
to  limit  its  public  utility  operations  to the  State  of  Missouri  and to
discontinue  operating as a public utility subject to ICC  regulation.  AmerenUE
intends to accomplish this plan by transferring its Illinois-based  electric and
natural gas businesses,  including its  Illinois-based  distribution  assets and
personnel  and  certain  of  its  transmission   assets,   to  the  Registrant's
subsidiary,   Central  Illinois  Public  Service  Company,   which  operates  as
AmerenCIPS.  AmerenUE's  electric  generating  facilities  and  certain  of  its
electric transmission  facilities in Illinois would not be part of the transfer.
The transfer of AmerenUE's  Illinois-based  utility  businesses will require the
approval  of the ICC,  the  FERC,  the  MoPSC and the  Securities  and  Exchange
Commission  (SEC) under the provisions of the Public Utility Holding Company Act
of 1935 (PUHCA).

     Upon receipt of these  regulatory  approvals and completion of the transfer
of its Illinois-based  utility businesses,  AmerenUE,  as it states in the above
referenced  Notice of  Withdrawal,  will no longer be subject to regulation as a
public utility by the ICC and as a result,  the ICC's approval will no longer be
required for the Pinckneyville and Kinmundy  combustion turbine generating units
to be transferred from Generating Company to AmerenUE. The Registrant intends to
continue with the intercompany  transfer of these electric generating facilities
and will continue to seek approvals from regulators having jurisdiction over the
transaction.  The  FERC is  required  to  approve  the  transaction.  As  stated
previously, ICC approval will no longer be necessary.  Further, the MoPSC is not
required to approve this transaction;  however,  the MoPSC has stated in filings
with the FERC that this  transaction  is  consistent  with and  supported by the
AmerenUE  electric rate settlement  approved by the MoPSC in August 2002. Due to
the fact that no state regulatory bodies will approve this transaction,  the SEC
will be required to approve this transaction under the PUHCA.

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     The  Registrant  is unable to  predict  the  ultimate  outcome of the above
referenced  regulatory  proceedings or the timing of the final  decisions of the
various  agencies.   The  timing  of  regulatory  approvals  of  these  proposed
transactions  are  not  anticipated  to  have  any  effect  on the  Registrant's
financial position, results of operations or liquidity.


                                    SIGNATURE

     Pursuant to the  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.

                                       AMEREN CORPORATION
                                       (Registrant)


                                       By      /s/ Martin J. Lyons
                                            ---------------------------------
                                       Name:       Martin J. Lyons
                                       Title:   Vice President and Controller
                                                (Principal Accounting Officer)

Date:  June 2, 2003


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