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):
                                 April 29, 2004

                               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


     On April 29, 2004,  the  Registrant  issued a press release  announcing its
earnings for the  quarterly  period ended March 31, 2004.  The press  release is
attached as Exhibit 99.1 and is incorporated herein by reference.

     The  information  furnished  pursuant to Item 12,  including  Exhibit 99.1,
shall not be  deemed  "filed"  for  purposes  of  Section  18 of the  Securities
Exchange  Act  of  1934  (the  "Exchange  Act")  or  otherwise  subject  to  the
liabilities  under that  Section and shall not be deemed to be  incorporated  by
reference into any filing of the Registrant  under the Securities Act of 1933 or
the Exchange Act.


     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

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

Date:  April 29, 2004

                                  Exhibit Index

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

 99.1         - Press release regarding earnings for the quarterly period ended
                March 31, 2004, issued on April 29, 2004 by Ameren Corporation.