FORM 5

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

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    Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
    Form 3 Holdings Reported
    Form 4 Transactions Reported

ANNUAL STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person* MacCarthy, John Peters	2. Issuer Name and Ticker or Trading Symbol Ameren Corporation AEE		6. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director 10% Owner Officer (give title below) Other (specify below)
(Last) (First) (Middle) P. O. Box 66149, MC-1370	3. I.R.S. Identification Number of Reporting Person, if an entity (voluntary)	4. Statement for Month/Year February 3, 2003
(Street) St. Louis, MO 63166-6149		5. If Amendment, Date of Original (Month/Year)	7. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person
(City) (State) (Zip)	Table I — Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1. Title of Security (Instr. 3)	2. Trans- action Date (Month/ Day/ Year)	2A. Deemed Execution Date, if any (Month/Day/ Year)	3. Trans- action Code (Instr. 8)	4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 & 5)			5. Amount of Securities Beneficially Owned at End of Issuer's Fiscal year (Instr. 3 & 4)	6. Owner- ship Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Trans- action Date (Month/ Day/ Year)	2A. Deemed Execution Date, if any (Month/Day/ Year)	3. Trans- action Code (Instr. 8)	Amount	(A) or (D)	Price		6. Owner- ship Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock, $.01 Par Value	12/31/02		L	70⁽¹⁾	A	41.755	6,566	D
Common Stock, $.01 Par Value							5,000	I⁽²⁾	By Trust

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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FORM 5 (continued)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security

(Instr. 3)

2. Conver-
sion or
Exercise
Price of Derivative Security

3. Trans-
action Date

(Month/
Day/
Year)

3A. Deemed
Execution
Date,
if any
(Month/
Day/
Year)

4. Trans-
action
Code

(Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D)

(Instr. 3, 4 & 5)

6. Date Exercisable
and Expiration
Date
(Month/Day/
Year)

7. Title and Amount of Underlying Securities
(Instr. 3 & 4)

8. Price of Derivative Security
(Instr. 5)

9. Number of
Derivative
Securities
Beneficially
Owned
at End of Year
(Instr. 4)

10. Owner-
ship Form
of Deriv-
ative
Security:
Direct (D)
or Indirect (I)
(Instr. 4)

11. Nature of Indirect Beneficial Ownership
(Instr. 4)

(A)

(D)

Date Exer-cisable

Expira-
tion
Date

Title

Amount or Number of
Shares

Explanation of Responses:

(1) Stock was acquired during the fourth quarter of 2002 through reinvested dividends.
(2) Shares are registered in a trust for which his wife and children serve as trustee, and Mr. MacCarthy is not the beneficial owner of such shares.

By: /s/ G. L. Waters
G. L. Waters, Asst. Secy. for John P. MacCarthy
**Signature of Reporting Person

02/03/03
Date

**Intentional misstatements or omissions of facts constitute Federal Criminal Violations.
See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed.
If space is insufficient, See Instruction 6 for procedure.

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MACCARTHY JOHN PETERS 5