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):
                                January 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

     On January 30, 2003, the Registrant issued a press release  announcing that
the  Securities  and Exchange  Commission  (SEC) has  approved the  Registrant's
proposed  acquisition of CILCORP Inc. from The AES Corporation  under the Public
Utility Holding  Company Act. The press release states that no other  regulatory
approvals are required and the SEC approval paves the way for the closing of the
transaction in the near future.  The press release is attached as Exhibit 99 and
is incorporated herein by reference.


ITEM 7.  EXHIBITS

         (c) Exhibits.

             99 Press release, dated January 30, 2003, issued by the
             Registrant.



                                    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:       Controller
                                            (Principal Accounting Officer)


Date:  January 30, 2003


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                                  Exhibit Index
                                  -------------


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

    99     - Press release dated January 30, 2003, issued by Ameren Corporation.



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[GRAPHIC OMITTED][GRAPHIC OMITTED]
                                                                One Ameren Plaza
                                                            1901 Chouteau Avenue
                                                             St. Louis, MO 63103


Contact:

Analysts:                           Media:
Bruce Steinke                       Susan Gallagher
(314) 554-2574                      (314) 554-2175

FOR IMMEDIATE RELEASE
---------------------


                   SECURITIES AND EXCHANGE COMMISSION APPROVES
                    AMEREN'S PROPOSED ACQUISITION OF CILCORP

ST. LOUIS, MO, Jan. 30, 2003-Ameren Corporation (NYSE: AEE) announced today that
the  Securities  and  Exchange  Commission  has  approved  the  proposed  Ameren
acquisition  of CILCORP  Inc.  from The AES  Corporation  (NYSE:  AES) under the
Public Utility Holding Company Act.

     No other regulatory approvals are required,  but the transaction is subject
to customary closing  conditions.  The U.S.  Department of Justice has completed
its review,  conducted under the Hart-Scott-Rodino  Antitrust  Improvements Act.
The Illinois Commerce  Commission and the Federal Energy  Regulatory  Commission
have also approved the transaction.

     Ameren  serves 1.5  million  electric  customers  and  300,000  natural gas
customers  in a  44,500-square-mile  area of Missouri  and  Illinois.  CILCORP's
largest  subsidiary,  Central  Illinois  Light  Company---CILCO,  serves 200,000
electric and more than 200,000 natural gas customers.


Safe Harbor Statement
---------------------
     This news release may include forward-looking statements. Actual events and
results may differ  materially from those  projected.  Factors that could affect
actual  results  are  discussed  in Ameren's  filings  with the  Securities  and
Exchange  Commission,  and readers are encouraged to read those filings to learn
more about the risk factors associated with Ameren's businesses.

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