EXHIBIT (11)(a)


January 12, 2006

Morgan Stanley Institutional Fund, Inc.
1221 Avenue of the Americas
New York, New York  10020

Ladies and Gentlemen:

         We have acted as counsel for Morgan Stanley Institutional Fund, Inc.
(the "Fund") in connection with the proposed acquisition by the Large Cap
Relative Value Portfolio of the Fund (the "Acquiring Portfolio") of
substantially all of the assets and the assumption of substantially all of the
liabilities of the Equity Portfolio of Morgan Stanley Institutional Fund Trust
(the "Acquired Portfolio") in exchange solely for an equal aggregate value of
shares of the Acquiring Portfolio to be distributed thereafter to shareholders
of the Acquired Portfolio (the "Reorganization"). This opinion is furnished in
connection with the Fund's Registration Statement on Form N-14 under the
Securities Act of 1933, as amended (the "Registration Statement"), relating to
the Class A and Class B shares of the Acquiring Portfolio, each with a par value
of $0.001 per share (the "Shares"), to be issued in the Reorganization.

         We have examined such statutes, regulations, corporate records and
other documents and reviewed such questions of law as we deemed necessary or
appropriate for the purpose of this opinion. As to matters of Maryland law
contained in this opinion, we have relied upon the opinion of Ballard Spahr
Andrews & Ingersoll, LLP, dated January 12, 2006.

         Based upon the foregoing, we are of the opinion that subsequent to the
approval by the shareholders of the Acquired Portfolio of the Agreement and Plan
of Reorganization between the Fund, on behalf of the Acquiring Portfolio, and
Morgan Stanley Institutional Fund Trust, on behalf of the Acquired Portfolio,
set forth in the proxy statement and prospectus constituting a part of the
Registration Statement (the "Proxy Statement and Prospectus"), the Shares, upon
issuance in the manner referred to in the Registration Statement, will be
legally issued, fully paid and non-assessable shares of the Acquiring Portfolio.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the use of our name in the Proxy Statement and
Prospectus constituting a part thereof. We have consented to the filing of this
opinion as an exhibit to the Registration Statement and to the reference to us
under the heading "Legal Matters" in the Prospectus forming a part of the
Registration Statement. In giving this consent, we do not concede that we are in
the category of persons whose consent is required under Section 7 of the 1933
Act.


Very truly yours,



/s/ Clifford Chance US LLP