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):
                                 January 7, 2002

                               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


     On January 7, 2002,  the  Registrant  issued a press release  outlining the
details of the January 3, 2002 Missouri Public Service  Commission  (MPSC) order
related to filing  requirements  and a new procedural  schedule for the earnings
complaint  case filed by the MPSC staff  against  Union  Electric  Company d/b/a
AmerenUE,  the  Registrant's  subsidiary,  in July 2001.  The press release also
announces a revision  to the  Registrant's  2001  earnings  estimate.  The press
release is attached as Exhibit 99 and is incorporated herein by reference.


        (c) Exhibits.

            99   Press release, dated January 7, 2002, 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/ Warner L. Baxter
                                               Warner L. Baxter
                                        Senior Vice President, Finance
                                         (Principal Financial Officer)

Date:  January 8, 2002

                                  Exhibit Index

Exhibit No.                  Description

     99     - Press release dated January 7, 2002, issued by Ameren Corporation.


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


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


     St.  Louis,  Mo.,  Jan. 7, 2002 --- Ameren  Corporation  (NYSE:  AEE) today
outlined  the Jan. 3, 2002,  Missouri  Public  Service  Commission  (MPSC) order
related to an earnings complaint case filed by the MPSC staff in July 2001. That
filing proposed to substantially  reduce  AmerenUE's annual electric revenues in
Missouri.  In the Jan. 3 order, the MPSC addressed filing requirements and a new
procedural schedule for this case.

     Specifically,  the MPSC ordered  that the parties  employ a July 1, 2000 to
June 30, 2001,  test year for determining  rates for AmerenUE's  Missouri retail
electric  operations,  with  updates to that test year being  permitted  through
Sept. 30, 2001. Originally in its complaint,  the MPSC staff had utilized a test
year of July 1, 1999 through June 30, 2000. In addition,  the MPSC stated in its
order that AmerenUE would be permitted to propose an incentive  regulation  plan
in this proceeding.

     Further in its order, the MPSC revised the procedural schedule in this case
to allow the parties  additional time to review data and file testimony,  due to
the  utilization of a more current test year.  Under the new schedule,  the MPSC
staff will file direct  testimony on March 1, 2002, with AmerenUE and the Office
of Public Counsel filing  rebuttal  testimony on May 10, 2002.  Hearings on this
matter are scheduled to begin July 11, 2002,  with the last hearing date set for
Aug. 2, 2002.

     The MPSC's order is consistent with a joint proposal  submitted by the MPSC
staff and AmerenUE and supported by the Office of Public Counsel.  A part of the
joint  proposal and order by the MPSC is that the company has agreed that if the
MPSC ultimately  determines that a rate decrease is warranted in this case, that
rate reduction  would be  retroactive  to April 1, 2002,  regardless of when the
commission issues its decision.
                                                -- more --

Add One

     "We believe that the commission  made a very prudent  decision in requiring
the parties to employ more current financial data in this case," said Charles W.
Mueller,  chairman and chief executive  officer of Ameren  Corporation.  "We are
also pleased to have the  opportunity  to present to the commission an incentive
regulation  plan in this case. We truly believe that incentive  regulation  will
result in a win-win  situation  for all  stakeholders,  as evidenced by the fact
that the incentive  regulation plan that we have operated under for the past six
years returned more than $425 million in benefits back to our customers."

     From  1995  until  June  30,  2001,  AmerenUE's  Missouri  retail  electric
customers benefited from innovative  incentive regulation that allowed customers
and shareholders to share any earnings above certain regulatory return-on-equity
thresholds.  The two,  three-year  plans allowed the company's  retail  electric
customers  to  receive  at least  half of all  company  earnings  above  certain
regulatory return-on-equity thresholds.

     With regard to Ameren  Corporation's 2001 earnings,  the company's previous
2001  earnings  per  share  estimate  of $3.30 to $3.45 per  share  assumed  and
incorporated a future form of incentive regulation, which included electric rate
reductions and additional customer credits.  Currently,  Ameren does not believe
that the impact of a future form of  incentive  regulation  will affect its 2001
net income.  As a result,  the company  estimates  2001  earnings per share will
range from $3.40 to $3.50.  This estimate  excludes a reduction in earnings of 5
cents per share  associated with the cumulative  effect of an accounting  change
due to the required adoption of the Statement of Financial  Accounting Standards
(SFAS) No. 133, which requires recording the fair value of derivative  financial
instruments  in the financial  statements.  Ameren's 2001 earnings and estimates
for 2002 earnings per share will be released Feb. 5, 2002, and a conference call
for financial  analysts and a live Internet  broadcast will be conducted on that
date to discuss this information.

     With assets of $10 billion,  Ameren  operating  companies serve 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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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;
the impact on the company of current  regulations  related to the  phasing-in of
the opportunity  for some customers to choose  alternative  energy  suppliers in
Illinois; the effects of increased competition in the future due to, among other
things,  deregulation of certain  aspects of the company's  business at both the
state and federal levels; the effects of withdrawal from the Midwest Independent
System Operator and membership in the Alliance Regional  Transmission  Operator;
future market prices for fuel and purchased power, electricity, and natural gas,
including the use of financial instruments; average rates for electricity in the
Midwest;  business  and economic  conditions;  the impact of the adoption of new
accounting  standards;  interest rates;  weather conditions;  fuel availability;
generation  plant  construction,  installation  and  performance;  the impact of
current environmental  regulations on utilities and generating companies and the
expectation that more stringent requirements will be introduced over time, which
could  potentially  have  a  negative  financial  effect;  monetary  and  fiscal
policies;  future  wages and  employee  benefit  costs;  competition  from other
generating  facilities  including  new  facilities  that may be developed in the
future; cost and availability of transmission  capacity for the energy generated
by the company's generating  facilities or required to satisfy energy sales made
by the company; and legal and administrative proceedings.

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