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):
                                  July 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


<PAGE>



ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS.

          (c)   Exhibits.

          99   Press release  regarding  earnings for the quarterly period ended
               June 30, 2003, issued on July 30, 2003 by Ameren Corporation (the
               Registrant).


ITEM 12. RESULTS OF OPERATIONS AND FINANCIAL CONDITION.

     On July 30, 2003,  the  Registrant  issued a press release  announcing  its
earnings for the  quarterly  period ended June 30,  2003.  The press  release is
attached as Exhibit 99 and is incorporated herein by reference.


                                    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:  July 30, 2003



                                       2





<PAGE>



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

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

  99           - Press release regarding earnings for the quarterly period ended
                 June 30, 2003, issued on July 30, 2003 by Ameren Corporation.








                                       3
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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):
                                  July 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 7. FINANCIAL STATEMENTS AND EXHIBITS.

          (c)   Exhibits.

          99   Press release  regarding  earnings for the quarterly period ended
               June 30, 2003, issued on July 30, 2003 by Ameren Corporation (the
               Registrant).

ITEM 12. RESULTS OF OPERATIONS AND FINANCIAL CONDITION.

     On July 30, 2003,  the  Registrant  issued a press release  announcing  its
earnings for the  quarterly  period ended June 30,  2003.  The press  release is
attached as Exhibit 99 and is incorporated herein by reference.

                                    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:  July 30, 2003

                                       2
Exhibit Index
                                  -------------

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

  99           - Press release regarding earnings for the quarterly period ended
                 June 30, 2003, issued on July 30, 2003 by Ameren Corporation.

                                       3