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                                                                     EXHIBIT 11



                     BALLARD SPAHR ANDREWS & INGERSOLL, LLP
                         1735 MARKET STREET, 51ST FLOOR
                     PHILADELPHIA, PENNSYLVANIA 19103-7599
                                 (215) 665-8500


                                         April 1, 1999

AIM Advisor Funds, Inc.
11 Greenway Plaza
Suite 100
Houston, Texas   77046

                  Re:  Shares of Stock AIM Advisor Funds, Inc.

Ladies & Gentlemen:

                  We have acted as counsel to AIM Advisor Funds, Inc., a
Maryland corporation (the "Company"), in connection with that certain Plan of
Reorganization (the "Plan") adopted by the Company's board of directors on
March 11, 1999 for AIM Advisor MultiFlex Fund ("MultiFlex Fund").

                  The Plan provides for the reclassification and change of
outstanding MultiFlex Fund shares into shares of AIM Advisor Flex Fund ("Flex
Fund") of the same class (the "Reorganization"). MultiFlex Fund and Flex Fund
are both separate series of shares of the Company's capital stock. Pursuant to
the Plan, all of the assets and liabilities of MultiFlex Fund will become the
assets and liabilities of Flex Fund, and each issued and outstanding share of
MultiFlex Fund will be changed into a fractional share of Flex Fund of the same
class that has a net asset value equal to the net asset value of the MultiFlex
Fund share immediately prior to the Reorganization. The value of each MultiFlex
Fund shareholder's account with Flex Fund after the Reorganization will be the
same as the value of such shareholder's account with MultiFlex Fund prior to
the Reorganization.

                  The opinion expressed below is based on the assumption that a
Registration Statement on Form N-14 with respect to the Class A, Class B and
Class C shares of Flex Fund to be issued to the MultiFlex Fund shareholders
pursuant to the Plan (the "Flex Fund Shares") will



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AIM Advisor Funds, Inc.
April 1, 1999
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have been filed by the Company with the Securities and Exchange Commission and
will have become effective before the Reorganization occurs.

                  Based on the foregoing, we are of the opinion that the Flex
Fund Shares, when issued by the Company to the shareholders of MultiFlex Fund
in accordance with the terms and conditions of the Plan, will be legally
issued, fully paid and nonassessable.

                  We express no opinion concerning the laws of any jurisdiction
other than the federal laws of the United States of America and the laws of the
State of Maryland.

                  We consent to the filing of this opinion as an Exhibit to the
Company's Registration Statement on Form N-14 and to the references to this
firm in such Registration Statement.

                                          Very truly yours,

                                    /s/ Ballard Spahr Andrews & Ingersoll, LLP



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