Exhibit 32.2


                           SECTION 1350 CERTIFICATION
                        OF PRINCIPAL FINANCIAL OFFICER OF
                               AMEREN CORPORATION
                         (required by Section 906 of the
                           Sarbanes-Oxley Act of 2002)


In connection  with the report on Form 10-Q for the quarterly  period ended June
30, 2004 of Ameren  Corporation (the "Company") as filed with the Securities and
Exchange  Commission on the date hereof (the "Form 10-Q"),  I, Warner L. Baxter,
chief financial officer of the Company,  certify, pursuant to 18 U.S.C. ss.1350,
as adopted pursuant to ss.906 of the Sarbanes-Oxley Act of 2002, that:

(1)  The Form 10-Q fully  complies  with the  requirements  of Section  13(a) or
     15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)); and

(2)  The information contained in the Form 10-Q fairly presents, in all material
     respects, the financial condition and results of operations of the Company.


Dated: August 9, 2004



                                          /s/ Warner L. Baxter
                                          -----------------------------------
                                          Warner L. Baxter
                                          Executive Vice President and
                                          Chief Financial Officer
                                          (Principal Financial Officer)