EXHIBIT 5.01


               [LETTERHEAD OF BROWN RUDNICK BERLACK ISRAELS LLP]




February 14, 2002

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

            RE: Registration Statement on Form S-4 of Brooks Automation, Inc.

Ladies and Gentlemen:

     We have acted as counsel to Brooks Automation, Inc., a Delaware corporation
(the "Company"), in connection with the preparation and filing with the
Securities and Exchange Commission of a Registration Statement on Form S-4 (the
"Registration Statement") pursuant to which the Company is registering under the
Securities Act of 1933, as amended (the "Act"), a total of 16,120,000 shares of
common stock, $.01 par value per share (the "Common Stock"). Pursuant to the
Registration Statement and an Amended and Restated Agreement and Plan of Merger
dated December 18, 2001 (the "Merger Agreement") by and among the Company, PRI
Automation Inc. ("PRI Automation") and Pontiac Acquisition Corp., in the form
filed as Exhibit 2.13 to the Registration Statement, the Company proposes to
issue to the holders of PRI Automation up to 16,120,000 shares of Common Stock
and associated junior Preferred Stock purchase rights pursuant to the Rights
Agreement dated as of July 23, 1997, as amended, between the Company and
Equiserve Trust Company N.A. (collectively the "Shares"). This opinion is being
rendered in connection with the filing of the Registration Statement. Unless
otherwise indicated, capitalized terms used herein shall have the meanings
ascribed thereto in the Merger Agreement.

      For purposes of this opinion, we have assumed, without any investigation:
(i) the legal capacity of each natural person; (ii) the full power and authority
of each entity and person other than the Company and Pontiac Acquisition Corp.
to execute, deliver and perform each document heretofore executed and delivered
or hereafter to be executed and delivered and to do each other act heretofore
done or hereafter to be done by such entity or person; (iii) the due
authorization by each entity or person other than the Company and Pontiac
Acquisition Corp. of each document heretofore executed and delivered or
hereafter to be executed and delivered and to do each other act heretofore done
or to be done by such entity or person; (iv) the due execution and delivery by
each entity or person other than the Company and Pontiac Acquisition Corp. of
each document heretofore executed and delivered or hereafter to be executed and
delivered by such entity or person; (v) the legality, validity, binding effect
and enforceability as to each entity or person other than the Company and
Pontiac Acquisition Corp. of each document heretofore executed and delivered or
hereafter to be executed and delivered and of each other act heretofore done or
hereafter to be done by such entity or person; (vi) the genuineness of each
signature on, and the completeness of, each document submitted to us as an
original; (vii) the conformity to the original of each document submitted to us
as a copy; (viii) the authenticity of the original of each document submitted to
us as a copy; (ix) the completeness, accuracy and proper indexing of all
governmental and judicial records searched;





Brooks Automation, Inc.
February 14, 2002
Page 2

and (x) no modification of any provision of any document, no waiver of any right
or remedy and no exercise of any right or remedy other than in a commercially
reasonable and conscionable manner and in good faith.

      In connection with this opinion, we have examined the following
(collectively, the "Documents"):

      (i)   the Certificate of Incorporation of the Company, as amended;

      (ii)  the Bylaws of the Company;

      (iii) the corporate minute books or other records of the Company;

      (iv)  a specimen certificate for the Common Stock incorporated by
            reference as Exhibit 4.01 to the Registration Statement; and

      (v)   the Merger Agreement.

      The opinions expressed herein are based solely upon: (i) our review of the
Documents; (ii) the representations and warranties of the Company, Pontiac
Acquisition Corp. and PRI Automation contained in the Merger Agreement and
the schedules and exhibits thereto; (iii) discussions with those of our
attorneys who have devoted substantive attention to the matters contained
herein; and (iv) such review of published sources of law as we have deemed
necessary.

      Our opinions contained herein are limited to the laws of The Commonwealth
of Massachusetts, the Delaware General Corporation Law and the federal law of
the United States of America.

      Based upon and subject to the foregoing, we are of the opinion that the
Shares to be issued by the Company under the circumstances contemplated in the
Registration Statement are duly authorized and, when delivered pursuant to the
Merger Agreement, will be validly issued, fully paid and non-assessable.

      We understand that this opinion is to be used in connection with the
Registration Statement. We consent to the filing of this opinion as an Exhibit
to said Registration Statement and to the reference to our firm wherever it
appears in the Registration Statement, including the joint proxy
statement/prospectus constituting a part thereof and any amendments thereto.
This opinion may be used in connection with the offering of the Shares only
while the Registration Statement, as it may be amended from time to time,
remains in effect.


Brooks Automation, Inc.
February 14, 2002
Page 3


                                  Very truly yours,

                                  BROWN RUDNICK BERLACK ISRAELS LLP

                                  By:  Brown, Rudnick, Freed & Gesmer, P.C.


                                  By: /s/ Samuel P. Williams
                                  --------------------------
                                        Samuel P. Williams,
                                      a Member Duly Authorized
DHM;SPW