EXHIBIT 5.1

Brooks Automation, Inc.
15 Elizabeth Drive
Chelmsford, Massachusetts 01824

     Re: Brooks Automation, Inc.
         $10,000,000 of Deferred Compensation Obligations

Ladies and Gentlemen:

      In connection with the proposed registration under the Securities Act of
1933, as amended, of $10,000,000 of deferred compensation obligations (the
"Obligations") of Brooks Automation, Inc., a Delaware corporation (the
"Company"), payable under the Brooks Automation, Inc. Deferred Compensation Plan
I (As Adopted Effective April 1, 2005) (the "Plan"), we have examined the
Certificate of Incorporation of the Company as amended to date, the By-laws of
the Company and the resolutions adopted to date by the Board of Directors of the
Company relating to the Plan and the Registration Statement. We have also
examined the Registration Statement on Form S-8, dated the date hereof, to be
filed with the Securities and Exchange Commission relating to such Obligations
(the "Registration Statement"), and have reviewed such matters of law as we have
deemed necessary for this opinion.

      In this connection, we have examined originals, or copies of originals
certified or otherwise identified to our satisfaction, of such records of the
Company and other corporate documents, have examined such questions of law and
have satisfied ourselves as to such matters of fact as we have considered
relevant and necessary as a basis for the opinions set forth herein. We have
assumed the authenticity of all documents submitted to us as originals, the
genuineness of all signatures, the legal capacity of all natural persons and the
conformity with the original documents of any copies thereof submitted to us for
our examination.

      Accordingly, based upon the foregoing, we are of the opinion that:

      The Obligations will be, when created in accordance with the Plan, valid
and binding obligations of the Company, enforceable in accordance with the terms
of the Plan, subject to (i) bankruptcy, insolvency, reorganization, arrangement
or other laws of general applicability relating to or affecting creditors'
rights, and (ii) general principles of equity, whether such enforcement is
considered in a proceeding at equity or law.

      We hereby consent to the filing of this opinion letter as an exhibit to
the Registration Statement and to all references to our firm included in or made
a part of the Registration Statement.

                                    Very truly yours,

                                    Brown Rudnick Berlack Israels LLP

                                        /s/ Brown Rudnick Berlack Israels LLP
                                    By:______________________________________