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):
                                December 5, 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) 621-3222


<PAGE>


ITEM 5. OTHER EVENTS

           On December 5, 2001, the Registrant issued a press release estimating
its overall financial exposure resulting from Enron Corp.'s bankruptcy filing.
The press release is attached as Exhibit 99 and is incorporated herein by
reference.


ITEM 7. EXHIBITS

        (c) Exhibits.

           99  Press release, dated December 5, 2001, issued by the Registrant.



                                    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/ Warner L. Baxter
                                                -----------------------------
                                                     Warner L. Baxter
                                                Senior Vice President, Finance
                                                 (Principal Financial Officer)


Date:  December 5, 2001


<PAGE>


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

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

  99    - Press release dated December 5, 2001, issued by Ameren Corporation.


<PAGE>
                                                                Exhibit 99
[GRAPHIC OMITTED][GRAPHIC OMITTED]

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

Contact:

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



                      AMEREN CORPORATION ESTIMATES EXPOSURE
                  RESULTING FROM ENRON CORP. BANKRUPTCY FILING

St. Louis, Mo., Dec. 5,  2001---Ameren  Corporation  (NYSE: AEE) today announced
that the company estimates its overall financial  exposure based on transactions
with Enron Corp. (NYSE:ENE) and its affiliates to be less than $10 million on an
after-tax basis.

The company's  overall financial  exposure includes accounts  receivable owed to
the company from Enron, which is less than $5 million on an after-tax basis. The
company's  overall  financial  exposure,  based on current market prices, is not
considered material to the company's  financial position,  results of operation,
or liquidity. Enron Corp. filed for bankruptcy on Dec. 2, 2001.

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.
                                      # # #
Safe Harbor Statement
Statements made in this release,  which are not based on historical  facts,  are
"forward-looking"  and, accordingly,  involve risks and uncertainties that could
cause actual results to differ  materially from those  discussed.  Although such
"forward-looking"  statements  have  been  made in good  faith  and are based on
reasonable assumptions,  there is no assurance that the expected results will be
achieved.  These statements include (without limitation) statements as to future
expectations,  beliefs, plans, strategies,  objectives,  events, conditions, and
financial  performance.  In connection with the "Safe Harbor"  provisions of the
Private Securities  Litigation Reform Act of 1995, the company is providing this
cautionary  statement  to identify  important  factors  that could cause  actual
results to differ materially from those anticipated. The following factors could
cause results to differ materially from management  expectations as suggested by
such forward-looking  statements:  the effects of regulatory actions,  including
changes in regulatory policy;  changes in laws and other  governmental  actions;
future market prices for fuel and purchased power, electricity, and natural gas,
including the use of financial  instruments;  business and economic  conditions;
the impact of the adoption of new accounting standards;  interest rates; weather
conditions; fuel availability; and legal and administrative proceedings.
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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):
                                December 5, 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) 621-3222
ITEM 5. OTHER EVENTS

           On December 5, 2001, the Registrant issued a press release estimating
its overall financial exposure resulting from Enron Corp.'s bankruptcy filing.
The press release is attached as Exhibit 99 and is incorporated herein by
reference.

ITEM 7. EXHIBITS

        (c) Exhibits.

           99  Press release, dated December 5, 2001, issued by the Registrant.

                                    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/ Warner L. Baxter
                                                -----------------------------
                                                     Warner L. Baxter
                                                Senior Vice President, Finance
                                                 (Principal Financial Officer)

Date:  December 5, 2001
Exhibit Index
                                  -------------

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

  99    - Press release dated December 5, 2001, issued by Ameren Corporation.
Exhibit 99
[GRAPHIC OMITTED][GRAPHIC OMITTED]

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

Contact:

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

                      AMEREN CORPORATION ESTIMATES EXPOSURE
                  RESULTING FROM ENRON CORP. BANKRUPTCY FILING

St. Louis, Mo., Dec. 5,  2001---Ameren  Corporation  (NYSE: AEE) today announced
that the company estimates its overall financial  exposure based on transactions
with Enron Corp. (NYSE:ENE) and its affiliates to be less than $10 million on an
after-tax basis.

The company's  overall financial  exposure includes accounts  receivable owed to
the company from Enron, which is less than $5 million on an after-tax basis. The
company's  overall  financial  exposure,  based on current market prices, is not
considered material to the company's  financial position,  results of operation,
or liquidity. Enron Corp. filed for bankruptcy on Dec. 2, 2001.

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.
                                      # # #
Safe Harbor Statement
Statements made in this release,  which are not based on historical  facts,  are
"forward-looking"  and, accordingly,  involve risks and uncertainties that could
cause actual results to differ  materially from those  discussed.  Although such
"forward-looking"  statements  have  been  made in good  faith  and are based on
reasonable assumptions,  there is no assurance that the expected results will be
achieved.  These statements include (without limitation) statements as to future
expectations,  beliefs, plans, strategies,  objectives,  events, conditions, and
financial  performance.  In connection with the "Safe Harbor"  provisions of the
Private Securities  Litigation Reform Act of 1995, the company is providing this
cautionary  statement  to identify  important  factors  that could cause  actual
results to differ materially from those anticipated. The following factors could
cause results to differ materially from management  expectations as suggested by
such forward-looking  statements:  the effects of regulatory actions,  including
changes in regulatory policy;  changes in laws and other  governmental  actions;
future market prices for fuel and purchased power, electricity, and natural gas,
including the use of financial  instruments;  business and economic  conditions;
the impact of the adoption of new accounting standards;  interest rates; weather
conditions; fuel availability; and legal and administrative proceedings.