EXHIBIT 24

                                POWER OF ATTORNEY

       WHEREAS, AMEREN CORPORATION, a Missouri corporation (herein referred to
as the "Company"), is required to file with the Securities and Exchange
Commission, under the Securities Act of 1933, a Registration Statement(s) and
any amendments thereto, covering the registration of Common Stock under the
Company's Employee Long-Term Savings Plan - IUOE No. 148 and Employee Long-Term
Savings Plan IBEW No. 702, as authorized by the Company's Board of Directors on
April 26, 2005; and

       WHEREAS, each of the below undersigned holds the office or offices in the
Company set opposite his or her name;

       NOW, THEREFORE, each of the undersigned hereby constitutes and appoints
Gary L. Rainwater and/or Thomas R. Voss and/or Warner L. Baxter and/or Steven R.
Sullivan the true and lawful attorneys-in-fact of the undersigned, for and in
the name, place and stead of the undersigned, to affix the name of the
undersigned to said Registration Statement(s) and any amendments thereto, and,
for the performance of the same acts, each with power to appoint in their place
and stead and as their substitute, one or more attorneys-in-fact for the
undersigned, with full power of revocation; hereby ratifying and confirming all
that said attorneys-in-fact may do by virtue hereof.

       IN WITNESS WHEREOF, the undersigned have hereunto set their hands this
26th day of April, 2005:

Susan S. Elliott, Director                         /s/ Susan S. Elliott
                                                --------------------------------

Gayle P. W. Jackson, Director                      /s/ Gayle P. W. Jackson
                                                --------------------------------

James C. Johnson, Director                         /s/ James C. Johnson
                                                --------------------------------

Richard A. Liddy, Director                         /s/ Richard A. Liddy
                                                --------------------------------

Gordon R. Lohman, Director                         /s/ Gordon R. Lohman
                                                --------------------------------

Richard A. Lumpkin, Director                       /s/ Richard A. Lumpkin
                                                --------------------------------

Paul L. Miller, Jr., Director                      /s/ Paul L. Miller, Jr.
                                                --------------------------------

Charles W. Mueller, Director                       /s/ C. W. Mueller
                                                --------------------------------

Douglas R. Oberhelman, Director                    /s/ Douglas R. Oberhelman
                                                --------------------------------

Harvey Saligman, Director                          /s/ Harvey Saligman
                                                --------------------------------

Patrick T. Stokes, Director                        /s/ Patrick T. Stokes
                                                --------------------------------

STATE OF MISSOURI )
                  ) SS.
CITY OF ST. LOUIS )

     On this 26th day of April, 2005, before me, the undersigned Notary Public
in and for said State, personally appeared the above-named directors of Ameren
Corporation, known to me to be the persons described in and who executed the
foregoing power of attorney and acknowledged to me that they executed the same
as their free act and deed for the purposes therein stated.

     IN TESTIMONY WHEREOF, I have hereunto set my hand and affixed my official
seal.

                                                  /s/ S. A. Kitchens
                                         --------------------------------------
                                                    S. A. Kitchens
                                              Notary Public - Notary Seal
                                                   STATE OF MISSOURI
                                                   St. Louis County
                                           My Commission Expires July 9, 2007