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 17, 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

     Reference is made to "Liquidity and Capital Resources" under  "Management's
Discussion  and  Analysis of  Financial  Condition  and Results of  Operations -
Financing" of the Registrant's  2002 Annual Report  incorporated by reference in
Item 7 of the Registrant's Form 10-K for the year ended December 31, 2002, for a
discussion  of  the   Registrant's   credit   facilities  and  credit  agreement
provisions.

     On July 17, 2003, the Registrant entered into two new credit agreements for
$470 million in revolving  credit  facilities  to be used for general  corporate
purposes,  including support of the Registrant's  commercial paper programs. The
$470 million in new facilities  includes a $235 million 364-day revolving credit
facility and a $235 million 3-year revolving  credit facility.  These new credit
facilities  replaced the  Registrant's  existing $270 million 364-day  revolving
credit  facility,  which matured on July 17, 2003, and a $200 million  facility,
which would have matured in December  2003. The new credit  facilities  contain,
among other terms and  conditions,  provisions  which require the  Registrant to
meet minimum ERISA funding  requirements  for its pension plan. The prior credit
facilities included more restrictive  provisions related to the funded status of
the Registrant's  pension plan, which are not present in the new facilities.  On
July 17, 2003, the Registrant also entered into an amendment of an existing $130
million  multi-year  credit facility that similarly  modified the  ERISA-related
provisions in this facility.  As a result,  all of the  Registrant's  facilities
require it to meet minimum  ERISA  funding  requirements,  but do not  otherwise
limit the underfunded status of the Registrant's pension plan.






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                                    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 18, 2003



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