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                                                                   EXHIBIT 11(a)

                    [KIRKPATRICK & LOCKHART LLP LETTERHEAD]

                                 March 22, 2000

AIM Investment Funds
11 Greenway Plaza, Suite 100
Houston, Texas 77046

Ladies and Gentlemen:

     You have requested our opinion, as counsel to AIM Investment Funds
("Trust"), as to certain matters regarding the issuance of Shares of AIM
Developing Markets Fund (the "Acquiring Portfolio"), a series of Trust, in
connection with the reorganization of AIM Emerging Markets Debt Fund (the
"Acquired Portfolio"), a series of Trust, into the Acquiring Portfolio, as
provided for in the Plan of Reorganization and Termination, effective as of
March 22, 2000 (the "Plan"). The Plan provides for the Acquired Portfolio to
transfer all of its assets to the Acquiring Portfolio in exchange solely for the
issuance of the Shares and the Acquiring Portfolio's assumption of all of the
liabilities of the Acquired Portfolio. (As used in this letter, the term
"Shares" means the Class A, Class B, and Class C shares of beneficial interest
in the Acquiring Portfolio.)

     As such counsel, we have examined certified or other copies, believed by
us to be genuine, of Trust's Agreement and Declaration of Trust dated as of May
7, 1998, as amended ("Agreement"), and Amended and Restated Bylaws, as amended,
and such other documents relating to its organization and operation as we have
deemed relevant to our opinion, as set forth herein. Our opinion is limited to
the laws and facts in existence on the date hereof, and it is further limited
to the laws (other than the conflict of law rules) of the State of Delaware
that in our experience are normally applicable to the issuance of shares of
beneficial interest by business trusts and to the Securities Act of 1933 ("1933
Act"), the Investment Company Act of 1940 ("1940 Act") and the regulations of
the Securities and Exchange Commission ("SEC") thereunder. With respect to
matters governed by the laws of the State of Delaware (excluding the securities
laws thereof), we have relied solely on the opinion of Potter Anderson &
Corroon, LLP, Delaware counsel to Trust, an executed copy of which is appended
hereto as Exhibit A.

     Based on the foregoing, we are of the opinion that the issuance of the
Shares has been duly authorized by Trust; and that, when sold in accordance
with the terms contemplated by Trust's registration statement on Form N-14
("Registration Statement"), including receipt by the Acquiring Portfolio of
full payment for the Shares and compliance with the 1933 Act and the 1940 Act,
the Shares will have been legally issued, fully paid, and non-assessable.

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AIM Investment Funds
March 22, 2000
Page 2

     We hereby consent to this opinion accompanying the Registration Statement
when it is filed with the SEC and to the reference to our firm in the
Registration Statement.

                                  Very truly yours,

                                  KIRKPATRICK & LOCKHART LLP

                                  By: /s/ ARTHUR J. BROWN
                                     --------------------------------
                                          Arthur J. Brown