[Brown, Rudnick, Freed & Gesmer]


                                   			August 20, 1997


Hologic, Inc. 
590 Lincoln Street
Waltham, MA 02154

RE:  Registration Statement on Form S-8

Ladies and Gentlemen:

	We are general counsel to Hologic, Inc., a Delaware corporation (the 
"Company").  We have been asked to deliver this opinion in connection with the 
preparation and filing with the Securities and Exchange Commission under the 
Securities Act of 1933, as amended (the "Act"), of a Registration Statement on 
Form S-8 (the "Registration Statement") relating to 500,000 shares of the 
Company's Common Stock, $.01 par value (the "Shares") and 500,000 Rights, as 
defined below.  The Rights are issuable pursuant to that certain Rights 
Agreement, dated as of December 22, 1992, as amended by Amendment No. 1, dated 
December 14, 1995, and Amendment No. 2, dated as of December 9, 1996 (the 
"Rights Agreement"), providing, in effect, for the delivery of a right (a 
"Right"), along with each share of Common Stock issued by the Company.

	The Shares are issuable pursuant to the Corporation's 1997 Employee 
Equity Incentive Plan (the "Plan").  The Rights are issuable in connection 
with the issuance of the Shares to be issued pursuant to the Plan.

	In connection with this opinion, we have examined and are familiar with 
originals or copies, certified or otherwise identified to our satisfaction, of 
the following documents (collectively, the "Documents"):

1.  A copy of the Certificate of Incorporation of the Company as in 
    effect on the date hereof;

2.  A copy of the Bylaws of the Company as in effect on the date hereof;

3.  The corporate records of the Company relating to the proceedings of 
    stockholders and directors of the Company;

4. The Plan;

5. The Rights Agreement; and

6. The Registration Statement.

	In giving our opinion, we have relied as to matters of fact upon 
certificates of officers of the Company.  For purposes of this opinion we have 
assumed without any investigation (1) the legal capacity of each natural 
person and (2) the genuineness of each signature, the completeness of each 
document submitted to us as an original and the conformity with the original 
of each document submitted to us as a copy.

	Our opinion hereafter expressed is based solely upon (1) our review of 
the Documents, (2) discussions with certain officers of the Company with 
respect to the Documents, (3) discussions with those of our attorneys who have 
devoted substantive attention to the matters contained herein and (4) such 
review of published sources of law as we have deemed necessary.

	Based upon and subject to the foregoing, we are of the opinion that the 
Shares have been duly authorized and, when issued in accordance with the terms 
of the Plan, the Shares will be validly issued, fully paid and nonassessable.  
	The Rights have been duly authorized and, when issued in accordance with 
the terms of the Rights Agreement, will be validly issued, fully paid and 
nonassessable.

	We hereby consent to the filing of this opinion as Exhibit 5 to the 
Registration Statement and to the reference to our firm wherever it appears in 
the Registration Statement.

                             Very truly yours,

                             BROWN, RUDNICK, FREED & GESMER, P.C.
                             By:  Brown, Rudnick, Freed & Gesmer, a 
                                  partner


                             By: /s/ Philip J. Flink
                                 -------------------
                                 Philip J. Flink, a Member
                                 hereunto duly authorized