<SUBMISSION>
<ACCESSION-NUMBER>0000908737-01-500100
<TYPE>424B3
<PUBLIC-DOCUMENT-COUNT>1
<FILING-DATE>20010703
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>IRON MOUNTAIN INC/PA
<CIK>0001020569
<ASSIGNED-SIC>4220
<IRS-NUMBER>232588479
<STATE-OF-INCORPORATION>PA
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>424B3
<ACT>33
<FILE-NUMBER>333-91577
<FILM-NUMBER>1674585
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>745 ATLANTIC AVENUE
<CITY>BOSTON
<STATE>MA
<ZIP>02111-
<PHONE>6175354766
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>745 ATLANTIC AVENUE
<CITY>BOSTON
<STATE>MA
<ZIP>02111-
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>PIERCE LEAHY CORP
<DATE-CHANGED>19960807
</FORMER-COMPANY>
</FILER>
<DOCUMENT>
<TYPE>424B3
<SEQUENCE>1
<FILENAME>imis424b.txt
<TEXT>

Prospectus Supplement No. 1                     Filed Pursuant to Rule 424(b)(3)
(To Prospectus Dated February 8, 2000)          Registration No. 333-91577

                              Prospectus Supplement
                                 July 3, 2001

This  prospectus  supplement  relates to the resale by the  holders of shares of
Common Stock.

This prospectus  supplement  should be read in conjunction  with, and may not be
delivered or utilized without, the prospectus dated February 8, 2000.

The information appearing under the heading "Selling  Shareholders" on page 8 in
the  prospectus  is  hereby  deleted  in its  entirety  and  replaced  with  the
following:

The selling  shareholders  are Kent P. Dauten,  B. Thomas  Golisano,  C. Richard
Reese,  Vincent J. Ryan and Schooner Capital LLC, a Delaware  limited  liability
company.  Prior to the  offering of shares  described  in this  prospectus,  the
selling  shareholders  beneficially  owned the following  shares.  The number of
shares beneficially owned by each person is determined according to the rules of
the Securities and Exchange  Commission,  and the information is not necessarily
indicative of  beneficial  ownership for any other  purpose.  The  percentage of
outstanding  shares  beneficially  owned  prior  to the  offering  assumes  that
55,757,378 shares were issued and outstanding as of June 2, 2001, the date as of
which the information in this table is given:

<TABLE>
<CAPTION>
                                                                                             Percentage of
                                  Shares Beneficially                                      Outstanding Shares
                                       Owned                Maximum Number of Shares       Beneficially Owned
 Selling Shareholder               Prior to Offering              Being Offered            Prior to Offering*
 -------------------              -------------------       ------------------------       ------------------
<S>                                 <C>                         <C>                              <C>

Kent P. Dauten                       1,015,664 (1)               1,009,227                        1.8%

B. Thomas Golisano                   1,243,977 (2)               1,232,113                        2.2%

C. Richard Reese                     1,561,458 (3)                 662,045                        2.8%

Vincent J. Ryan                      5,102,562 (4)               2,298,549                        9.2%

Schooner Capital LLC                 2,736,076 (5)               2,736,076                        4.9%

</TABLE>


* Includes all shares beneficially  owned, not just those being offered.  Except
as otherwise  indicated,  the persons  names in the table above have sole voting
and investment  power with respect to all shares shown as beneficially  owned by
them.

-----------

(1)      Mr. Dauten is a director of Iron  Mountain.  Includes 6,437 shares that
         Mr. Dauten has the right to acquire  pursuant to currently  exercisable
         options. Such shares are not being offered under this prospectus.

(2)      Mr.  Golisano is a director of Iron  Mountain.  Includes  11,864 shares
         that Mr.  Golisano  has the  right to  acquire  pursuant  to  currently
         exercisable  options.  Such  shares  are not being  offered  under this
         prospectus.

(3)      Mr. Reese is a director, Chairman of the Board, Chief Executive Officer
         and President of Iron Mountain.  Includes 25,164 shares of common stock
         held in  trusts  for the  benefit  of Mr.  Reese's  children  not being
         offered  under  this  prospectus,  as  to  which  Mr.  Reese  disclaims
         beneficial  ownership.  Also includes 874,249 shares of common stock as
         to which Mr. Reese shares  beneficial  ownership with Schooner  Capital
         LLC   ("Schooner")  as  a  result  of  a  1988  deferred   compensation
         arrangement, as amended, between Schooner and Mr. Reese relating to Mr.
         Reese's former services as President of the predecessor  corporation to
         Schooner.  Pursuant to such  arrangement,  upon the earlier to occur of
         (i) Schooner's sale or exchange of  substantially  all of the shares of
         common  stock held by Schooner  or (ii) the  cessation  of Mr.  Reese's
         employment  with Iron  Mountain,  Schooner is required to transfer such
         shares of common  stock to Mr.  Reese or remit to Mr.  Reese cash in an
         amount  equal to the then  current  fair market value of such shares of
         common stock.
<PAGE>

         Such shares are included in the maximum  number of shares being offered
         under this  prospectus  by  Schooner.  Schooner  has agreed to vote the
         shares of Common Stock subject to such  arrangement at the direction of
         Mr. Reese.

(4)      Mr. Ryan is a director of Iron Mountain. Includes (i) 6,437 shares that
         Mr.  Ryan has the right to acquire  pursuant to  currently  exercisable
         options;  (ii)  6,000  shares  held in a trust for the  benefit  of Mr.
         Ryan's  heirs,  as to which Mr.  Ryan  disclaims  beneficial  ownership
         except  to the  extent of his  pecuniary  interest  therein;  and (iii)
         55,500  shares  held by The  Schooner  Foundation  as to which Mr. Ryan
         disclaims beneficial ownership. Such shares are not being offered under
         this prospectus. Also includes 2,736,076 shares of common stock held by
         Schooner,  as to which Mr.  Ryan has sole voting  power and  investment
         power as the  Chairman  of the  Board  of  Schooner  and the  principal
         stockholder  of Schooner  Capital  Trust,  the sole member of Schooner.
         Such shares are included in the maximum  number of shares being offered
         under this prospectus by Schooner.

(5)      Mr. Ryan is the  Chairman of the Board of  Schooner  and the  principal
         shareholder of Schooner Capital Trust, the sole member of Schooner, and
         accordingly,  has sole voting and investment  power with respect to the
         shares of common stock held by  Schooner.  Includes  874,249  shares of
         common stock as to which Schooner shares beneficial  ownership with Mr.
         Reese as  described  in footnote  (3).  Schooner has agreed to vote the
         shares of common stock subject to such  arrangement at the direction of
         Mr. Reese.
</TEXT>
</DOCUMENT>
</SUBMISSION>
