Exhibit 5.1



                              SULLIVAN & WORCESTER LLP
                               ONE POST OFFICE SQUARE
                             BOSTON, MASSACHUSETTS 02109
                                   (617) 338-2800
                                FAX NO. 617-338-2880
     IN WASHINGTON, D.C.                                   IN NEW YORK CITY
     1666 K STREET, N.W.                                   565 FIFTH AVENUE
   WASHINGTON, D.C. 20006                              NEW YORK, NEW YORK 10017
       (202) 775-8190                                       (212) 486-8200
    FAX NO. 202-293-2275                                 FAX NO. 212-758-2151



                                  May 24, 2002

Iron Mountain Incorporated
745 Atlantic Avenue
Boston, Massachusetts  02111

Ladies and Gentlemen:

         In connection with the  registration  under the Securities Act of 1933,
as  amended  (the  "Act"),  by  Iron  Mountain   Incorporated,   a  Pennsylvania
corporation (the "Company"),  of 1,352,543 shares of its Common Stock, par value
$.01 per share (the  "Registered  Shares"),  that are to be  offered  and may be
issued under the Company's  2002 Stock  Incentive  Plan (the "2002  Plan"),  the
following  opinion  is  furnished  to you to be filed  with the  Securities  and
Exchange   Commission  (the  "Commission")  as  Exhibit  5.1  to  the  Company's
registration statement on Form S-8 (the "Registration Statement") under the Act.

         We have  acted  as  counsel  to the  Company  in  connection  with  the
Registration Statement,  and we have examined originals or copies,  certified or
otherwise  identified to our satisfaction,  of the Registration  Statement,  the
Amended and Restated  Articles of  Incorporation  of the Company as presently in
effect,  corporate  records of the Company,  and such other documents as we have
considered necessary in order to furnish the opinion hereinafter set forth.

         We express no opinion herein as to the laws of any  jurisdiction  other
than the  Commonwealth  of  Massachusetts  and the  federal  laws of the  United
States,  and we  express no  opinion  as to state  securities  or blue sky laws.
Insofar as this opinion  involves matters of Pennsylvania law we have, with your
permission,  relied  solely on the opinion of Ballard Spahr Andrews & Ingersoll,
LLP, a copy of which is being filed herewith as Exhibit 5.2 to the  Registration
Statement,  and our  opinion is subject to the  exceptions,  qualifications  and
limitations therein expressed.

         Based on and subject to the foregoing, we are of the opinion that, when
issued in  accordance  with the terms of the 2002 Plan and the  options or other
rights  granted  thereunder,  the  Registered  Shares  will be duly  authorized,
validly issued, fully paid and nonassessable by the Company.


         We hereby  consent to the  filing of this  opinion as an exhibit to the
Registration  Statement  and to the  reference  to our  firm  in the  Prospectus
forming a part of the Registration  Statement. In giving such consent, we do not
thereby  admit that we come  within the  category  of persons  whose  consent is
required  under  Section  7 of the  Act  or the  rules  and  regulations  of the
Commission promulgated thereunder.

                                            Very truly yours,

                                            /s/ SULLIVAN & WORCESTER LLP