Exhibit 5.2

               Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.

                              One Financial Center
                           Boston, Massachusetts 02111
                                                                617 542 6000
                                                                617 542 2241 fax

                                October 20, 2006

ARIAD Pharmaceuticals, Inc.
26 Landsdowne Street
Cambridge, MA 02139

Ladies and Gentlemen:

      This opinion is furnished to you in connection with a Prospectus
Supplement, dated October 20, 2006 (the "Prospectus Supplement"), to (i) a
Registration Statement on Form S-3, Registration No. 333-122909, and (ii) a
Registration Statement on Form S-3 filed pursuant to Rule 462(b) related
thereto, Registration No. 333-138087 (collectively, the "Registration
Statements") filed by ARIAD Pharmaceuticals, Inc., a Delaware corporation (the
"Company"), with the Securities and Exchange Commission (the "Commission") under
the Securities Act of 1933, as amended (the "Securities Act"), with respect to
the sale of an aggregate of 1,098,125 shares (the "Shares") of its common stock,
$0.001 par value per share (the "Common Stock"), including 143,234 shares
subject to an underwriter's option, to Credit Suisse Securities (USA) LLC (the
"Underwriter") pursuant to an Underwriting Agreement dated October 19, 2006
between the Company and the Underwriter (the "Underwriting Agreement"), which
Underwriting Agreement will be filed as an exhibit to a Current Report on Form
8-K and incorporated by reference into the Registration Statements.

      In connection with this opinion, we have examined the Company's
Certificate of Incorporation, as amended, and Restated Bylaws, as amended; the
minutes of all pertinent meetings of directors of the Company relating to the
Registration Statements, the Prospectus Supplement and the transactions
contemplated thereby; such other records of the corporate proceedings of the
Company and certificates of the Company's officers as we deemed relevant for the
purposes of rendering the opinions in this letter; the Registration Statements
and the exhibits thereto filed with the Commission; and the Prospectus
Supplement.

      In our examination, we have assumed the genuineness of all signatures, the
legal capacity of natural persons, the authenticity of all documents submitted
to us as originals, the conformity to original documents of all documents
submitted to us as certified, photostatic or facsimile copies and the
authenticity of the originals of such copies.

      Based upon the foregoing, and subject to the limitations set forth below,
we are of the opinion that the Shares, when issued by the Company and delivered
by the Company against payment therefor as contemplated by the Underwriting
Agreement, will be duly and validly issued, fully paid and non-assessable shares
of the Common Stock.

      Our opinion is limited to the General Corporation Laws of the State of
Delaware (including the applicable provisions of the Delaware Constitution and
the reported judicial decisions interpreting such laws) and the United States
Federal Laws, and we express no opinion


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Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.

October 20, 2006
Page 2


with respect to the laws of any other jurisdiction. No opinion is expressed
herein with respect to the qualification of the Shares under the securities or
blue sky laws of any state or any foreign jurisdiction. To the extent that any
applicable document is stated to be governed by the laws of another
jurisdiction, we have assumed for purposes of this opinion that the laws of such
jurisdiction are identical to the state laws of the State of Delaware.

      Please note that we are opining only as to the matters expressly set forth
herein, and no opinion should be inferred as to any other matters. This opinion
is based upon currently existing statutes, rules, regulations and judicial
decisions, and we disclaim any obligation to advise you of any change in any of
these sources of law or subsequent legal or factual developments which might
affect any matters or opinions set forth herein.

      We hereby consent to the filing of this opinion with the Commission as an
exhibit to a Current Report on Form 8-K and the Registration Statements in
accordance with the requirements of Item 601(b)(5) of Regulation S-K under the
Securities Act and to the use of this Firm's name therein and in the Prospectus
Supplement under the caption "Legal Matters." In giving such consent, we do not
hereby admit that we are in the category of persons whose consent is required
under Section 7 of the Securities Act or the rules and regulations of the
Commission.

                         Very truly yours,

                         /s/ Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.

                         Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.