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                                                                    EXHIBIT a(3)

                                SECOND AMENDMENT
                                       TO
                       AGREEMENT AND DECLARATION OF TRUST
                                       OF
                                AIM SERIES TRUST


         THIS SECOND AMENDMENT TO AGREEMENT AND DECLARATION OF TRUST OF AIM
SERIES TRUST (the "Amendment") is entered into as of the 11th day of February,
2000, among C. Derek Anderson, Frank S. Bayley, Robert H. Graham and Ruth H.
Quigley, as Trustees, and each person who became or becomes a Shareholder in
accordance with the terms set forth in that certain Agreement and Declaration of
Trust of AIM Series Trust, a Delaware business trust (the "Trust"), entered into
as of May 7, 1998, as amended (the "Agreement").

         WHEREAS, Sections 2.3 and 9.7 of the Agreement empower the Trustees
without Shareholder action to amend the Agreement in order to change the
designations of the Portfolios and the Classes thereof; and

         WHEREAS, the Trustees on November 3, 1999, acting pursuant to Section
9.3 of the Agreement, approved the termination of the Advisor Class of the
Portfolio and the conversion of shares of such Advisor Class into shares of
Class A of the Portfolio;

         NOW, THEREFORE, the Trustees hereby amend the Agreement as follows:

         1. Capitalized terms not specifically defined in this Amendment shall
have the meanings ascribed to them in the Agreement.

         2. Schedule A to the Agreement is hereby deleted in its entirety and a
new Schedule A to the Agreement is substituted to read in its entirety as
follows:

                                   "SCHEDULE A

         AIM Series Trust shall be divided into the following Portfolios, each
of which shall have three Classes (Class A, Class B and Class C):

                             AIM Global Trends Fund

Dated: February 11th, 2000"

         3. Except for the above change in Schedule A to the Agreement, the
Agreement shall in all other respects remain in full force and effect.

         4. This Amendment may be executed in any number of counterparts and by
different parties hereto in separate counterparts, each of which when so
executed shall be deemed to be an original and all of which taken together shall
constitute one and the same Amendment.


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         IN WITNESS WHEREOF, the undersigned, being all of the Trustees of the
Trust, have executed this Second Amendment to Agreement and Declaration of Trust
of AIM Series Trust as of the day and year first above written.


/s/ C. DEREK ANDERSON                        /s/ ROBERT H. GRAHAM
-----------------------------------          -----------------------------------
C. Derek Anderson, Trustee                   Robert H. Graham, Trustee


/s/ FRANK S. BAYLEY                          /s/ RUTH H. QUIGLEY
-----------------------------------          -----------------------------------
Frank S. Bayley, Trustee                     Ruth H. Quigley, Trustee


                         [THIS IS THE SIGNATURE PAGE FOR
           THE SECOND AMENDMENT TO AGREEMENT AND DECLARATION OF TRUST
                              OF AIM SERIES TRUST]


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