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):
                                October 24, 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 12. RESULTS OF OPERATIONS AND FINANCIAL CONDITION.

          On October 24, 2003, the Registrant issued a press release  announcing
its  earnings  for the  quarterly  period ended  September  30, 2003.  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.


                                    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: October 24, 2003

                                       2



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

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

  99.1       - Press release  regarding  earnings for the quarterly period ended
               September  30,  2003,  issued  on  October  24,  2003  by  Ameren
               Corporation.




                                       3