Exhibit 5
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                [LETTERHEAD OF COZEN AND O'CONNOR APPEARS HERE]



                                 July 11, 1997



Pierce Leahy Corp.
631 Park Avenue
King of Prussia, PA 19406

     Re:  Registration Statement on Form S-8
          Relating to Pierce Leahy Corp.
          Non-Qualified Stock Option Plan and
          1997 Stock Option Plan
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Ladies and Gentlemen:

     As counsel to Pierce Leahy Corp. (the "Company"), we have assisted in the
preparation of the Company's Registration Statement on Form S-8 (the
"Registration Statement") to be filed with the Securities and Exchange
Commission under the Securities Act of 1933, as amended, relating to 1,114,174
shares of the Company's Common Stock, $.01 par value (the "Common Stock"), that
may be issued under the Pierce Leahy Corp. Non-Qualified Stock Option Plan (the
"Non-Qualified Plan") and 1,500,000 shares of Common Stock that may be issued
under the Company's 1997 Stock Option Plan (together with the Non-Qualified
Plan, the "Plans").

     In connection therewith, we have examined the Company's Articles of
Incorporation, as amended, Bylaws, as amended, and such corporate records and
other documents as we have deemed appropriate.  In all examinations of
documents, instruments and other papers, we have assumed the genuineness of all
signatures on original and certified documents and the conformity to original
and certified documents of all copies submitted to us as conformed, photostatic
or other copies.  As to matters of fact which have not been independently
established, we have relied upon representations of officers of the Company.

     Based upon the foregoing examination, information and assumptions, it is
our opinion that the shares of Common Stock to be offered under the Plans are
duly authorized and, when issued and sold to the participants pursuant to the
terms of the Plans, as applicable, will be legally issued, fully paid and non-
assessable.

     We hereby expressly consent to the inclusion of this opinion as an exhibit
to the Registration Statement.

                         Very truly yours,



                         COZEN AND O'CONNOR