SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* WILLIS SAMUEL E (Last) (First) (Middle) P. O. BOX 66149 (Street) ST. LOUIS MO 63166-6149 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol AMEREN CORP [ AEE ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner Officer (give title below) X Other (specify below) Vice President of Subsidiary
	3. Date of Earliest Transaction (Month/Day/Year) 03/09/2004
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, $.01 Par Value								1,659	I	By 401K
Common Stock, $.01 Par Value								2,246	I	By ESOP
Common Stock, $.01 Par Value								2,246(1)	I	By Spouse
Common Stock, $.01 Par Value	03/09/2004		S		687(2)	D	$47.0562	8,263	D

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. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option	$35.875							04/25/1997	04/25/2005	Common Stock, $.01 Par Value	700		700	D
Stock Option	$43							02/07/1998	02/07/2006	Common Stock, $.01 Par Value	2,500		3,200	D
Stock Option	$38.5							02/10/1999	02/10/2007	Common Stock, $.01 Par Value	3,400		6,600	D
Stock Option	$39.25							04/28/2000	04/28/2008	Common Stock, $.01 Par Value	9,700		16,300	D
Stock Option	$36.625							02/12/2001	02/12/2009	Common Stock, $.01 Par Value	10,700		27,000	D
Stock Option	$31							02/11/2002	02/11/2010	Common Stock, $.01 Par Value	7,050		34,050	D

Explanation of Responses:

1. Held in name of spouse, and the undersigned disclaims any beneficial interest in such shares.

2. Represents 330 shares, 223 shares and 134 shares of restricted stock issued in 2001, 2002 and 2003 respectively and sold to cover Mr. Willis' tax liability for acquiring restricted shares that have vested.

Remarks:

	G. L. Waters, Asst. Secy. for Samuel E. Willis	03/10/2004
	** Signature of Reporting Person	Date
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).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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