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):
                                  May 17, 2001

                               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) 554-2715


           On May 17, 2001, the Registrant issued a press release recommending
that its stockholders not accept TRC Capital Corporation's mini-tender offer to
purchase up to 4,000,000 shares of the Registrant's outstanding common stock at
an offer price of $40.00 per share. The press release is attached as Exhibit 99
and is incorporated herein by reference.


(c)      Exhibits.

            99    Press release, dated May 17, 2001, issued by the Registrant.


           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/ Donald E. Brandt
                                                Donald E. Brandt
                                         Senior Vice President, Finance
                                          (Principal Financial Officer)

Date:  May 17, 2001

                                                             Exhibit Index

Exhibit No.                                    Description

     99 - Press release dated May 17, 2001, issued by Ameren Corporation.

News Release                                                       Exhibit 99
One Ameren Plaza
1901 Chouteau Avenue
St. Louis, MO 63103


        Investor:                   Media:
           Lynn Barnes                      Susan Gallagher
         (314) 554-4829             (314) 554-2175

                          NOT ACCEPT MINI-TENDER OFFER

                 St. Louis, Mo., May 17, 2001---Ameren Corporation (NYSE:AEE)
        strongly recommends that stockholders not accept TRC Capital
        Corporation's mini-tender offer to purchase up to 4,000,000 shares of
        Ameren outstanding common stock, or approximately 2.9% of Ameren's
        outstanding shares, at an offer price of $40.00 per share.
                 TRC's offer price of $40.00 per share is less than Ameren's
        closing price on May 10, 2001, the day prior to the date of TRC's offer,
        and is less than Ameren's current trading price. TRC's offer states that
        it can be withdrawn at any time for any reason.
                 The Securities and Exchange Commission has said that
        mini-tender offers "have been increasingly used to catch investors off
        guard" and that investors "may end up selling their securities at
        below-market prices." The combination of the offer's current
        below-market price and TRC's right to withdraw the offer at any time
        enhances the risk that the offer will only proceed to consummation if at
        the time of purchase the offer price is below market.
                 Ameren suggests stockholders direct questions about the
        mini-tender offer to their investment advisers. Investors can obtain
        more information about mini-tender offers by visiting the SEC's Web site
                 With assets of $10 billion, Ameren serves 1.5 million electric
        customers and 300,000 natural gas customers in a 44,500-square-mile area
        of Missouri and Illinois.

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