As filed with the Securities and Exchange Commission on August 8, 1997
                                                       Registration No.

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                 --------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                  ------------

                           IRON MOUNTAIN INCORPORATED
               (Exact name of issuer as specified in its charter)

         Delaware                                  04-3107342
 (State or other jurisdiction of                (I.R.S. Employer
incorporation or organization)                 Identification No.)


                745 Atlantic Avenue, Boston, Massachusetts 02111
                                 (617) 357-4455
           (Address of Principal Executive Offices including zip code)
                                  -------------

              Iron Mountain Incorporated 1995 Stock Incentive Plan
                            (Full titles of the plan)
                                  ------------

                                C. Richard Reese
                            Chairman of The Board of
                      Directors and Chief Executive Officer
                           Iron Mountain Incorporated
                               745 Atlantic Avenue
                           Boston, Massachusetts 02111
                                 (617) 357-4455
            (Name, address and telephone number of agent for service)
                                  -------------

                                    Copy to:
                             William J. Curry, Esq.
                            Sullivan & Worcester LLP
                             One Post Office Square
                           Boston, Massachusetts 02109
                                 (617) 338-2800
                                ----------------

The prospectus  meeting the  requirements of Section 10(a) of the Securities Act
of 1933, as amended,  which is being provided to  participants in the 1995 Stock
Incentive Plan in conjunction with this  Registration  Statement also relates to
the shares  registered under the Registration  Statement on Form S-8 dated April
9, 1997 (File No. 333-24803) of Iron Mountain Incorporated.


<PAGE>
<TABLE>
<CAPTION>
                                                      ---------------

                                          CALCULATION OF REGISTRATION FEE


                                                        Proposed            Proposed Maximum
  Title of Securities         Amount to be          Maximum Offering            Aggregate                  Amount of
   to be Registered            Registered          Price Per Share(1)       Offering Price(1)           Registration Fee
   ----------------            ----------          ------------------       -----------------           ----------------
<S>                             <C>                     <C>                   <C>                      <C>

Common Stock, par
value $.01 per share             400,000                 $31.375               $12,550,000               $3,803.03

<FN>
(1)      With respect to the additional  400,000 shares  issuable under the 1995
         Stock Incentive Plan, the proposed maximum offering price per share and
         the  proposed  maximum  aggregate  offering  price have been  estimated
         solely for purpose of calculating the amount of the registration fee in
         accordance  with Rules  457(c) and 457(h) under the  Securities  Act of
         1933,  as  amended,  on the  basis of the  average  of the high and low
         prices of the Common  Stock on the Nasdaq  National Market on August 6,
         1997.  944,903 shares issuable under the 1995 Stock Incentive Plan were
         registered  under the Registrant's  registration  statement on Form S-8
         (File No.  333-24803),  filed  with  Commission  on April 9, 1997 and a
         filing  fee of  $4,425.28  was paid on such date with  respect  to such
         shares.
</FN>
</TABLE>



<PAGE>



PART II - INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

         Insofar as additional securities are being registered of the same class
as other  securities  for  which a  registration  statement  filed on this  form
relating to an employee  benefit plan is effective,  in accordance  with General
Instruction  E  to  the  Registration  Statement  on  Form  S-8,  Iron  Mountain
Incorporated  (the "Company")  hereby  incorporates by reference the contents of
the Company's  Registration  Statement on Form S-8 dated April 9, 1997 (File No.
333-24803) and omits the information  required by Part II from this Registration
Statement, other than Item 3 and Item 8, below, which have been updated.

Item 3.  Incorporation of Documents by Reference.

         The Company previously registered under the Securities Act an aggregate
of 944,903 shares of Common Stock offered  pursuant to the 1995 Stock  Incentive
Plan pursuant to a Registration  Statement on Form S-8 (File No. 333-2196) filed
with the Commission on April 9, 1997, which is incorporated in this Registration
Statement by reference.

         The  following  additional  documents,  which  have  been  filed by the
Company with the Commission, are incorporated by reference in and made a part of
this Registration Statement, as of their respective dates:

          (a)  The  Company's  Annual  Report on Form 10-K for the  fiscal  year
               ended December 31, 1996;

          (b)  The Company's Quarterly Report on Form 10-Q for the quarter ended
               March 31, 1997;

          (c)  The Company's Current Report on Form 8-K dated June 12, 1997; and

          (d)  The  description  of the Common Stock  contained in the Company's
               registration  statement on Form 8-A dated  January 18, 1996 (File
               No.  0-27584),  including any amendments or reports filed for the
               purpose of updating such description.

         All documents  subsequently  filed by the Company  pursuant to Sections
13(a),  13(c), 14 and 15(d) of the Securities  Exchange Act of 1934, as amended,
prior to the  filing of a  post-effective  amendment  which  indicates  that all
securities  offered  have been sold or which  deregisters  all  securities  then
remaining  unsold,  shall be  deemed to be  incorporated  by  reference  in this
Registration  Statement  and to be part  hereof  from the date of filing of such
documents.

         Any  statement  contained  in a document  incorporated  or deemed to be
incorporated  by reference  herein shall be deemed to be modified or  superseded
for  purposes  of this  Registration  Statement  to the extent  that a statement
herein,  or in any subsequently  filed document which also is or is deemed to be
incorporated by reference,  modifies or supersedes such statement. Any statement
so  modified  or  superseded  shall  not be  deemed,  except as so  modified  or
superseded, to constitute a part of this Registration Statement.

Item 8.  Exhibits.
                                   EXHIBIT INDEX

              Exhibit No.       Description

                  5        Opinion of Sullivan & Worcester LLP.*

                  23.1     Consent of Sullivan & Worcester LLP (contained in the
                           opinion of Sullivan & Worcester LLP filed herewith as
                           Exhibit 5).

                  23.2     Consent of Arthur Andersen LLP.*

                  24       Power of Attorney (included in signature page of this
                           Registration Statement).

*Filed herewith.

                                     II - 1


<PAGE>



                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the Company
certifies  that it has  reasonable  grounds to believe  that it meets all of the
requirements  for  filing  on Form S-8 and has  duly  caused  this  Registration
Statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized, in the City of Boston, Commonwealth of Massachusetts, on the 8th day
of August, 1997.

                                     IRON MOUNTAIN INCORPORATED



                                     By: /s/ C. Richard Reese
                                          C. Richard Reese
                                          Chairman of the Board,
                                          Chief Executive Officer and Director

         The  undersigned  Officers and Directors of Iron Mountain  Incorporated
(the "Company") hereby severally constitute C. Richard Reese, John F. Kenny, Jr.
and  David S.  Wendell,  and each of them  acting  singly,  our true and  lawful
attorneys to sign for us and in our names in the capacities  indicated below any
amendments  to  this   Registration   Statement  on  Form  S-8   (including  any
post-effective  amendments  hereto) and to file the same, with Exhibits  thereto
and other  documents in connection  therewith,  with the Securities and Exchange
Commission,  granting unto each of said attorneys, acting singly, full power and
authority to do and perform each and every act and thing  requisite or necessary
to be done in and about the premises, as fully to all intents and purposes as he
might or could do in person,  hereby  ratifying and confirming our signatures to
said amendments to this Registration  Statement signed by our said attorneys and
all else  that said  attorneys  may  lawfully  do and cause to be done by virtue
hereof.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement has been signed below by the following persons on behalf
of the Company and in the capacities and on the 8th day of August, 1997.

     Signatures                             Title


       /s/ C. Richard Reese
     C. Richard Reese                  Chairman, Chief
                                       Executive Officer and Director


       /s/ David S. Wendell
     David S. Wendell                  President, Chief Operating Officer and
                                       Director


       /s/ John F. Kenny
     John F. Kenny, Jr.                Executive Vice President and
                                       Chief Financial Officer


       /s/ Eugene B. Doggett
     Eugene B. Doggett                 Executive Vice President and Director





                                     II - 2


<PAGE>






     Constantin R. Boden               Director




     Arthur D. Little                  Director



       /s/ Vincent J. Ryan
     Vincent J. Ryan                   Director



       /s/ B. Thomas Golisano
     B. Thomas Golisano                Director



       /s/ Jean A. Bua
     Jean A. Bua                       Vice President and Corporate
                                       Controller










                                     II - 3
[{"type": "S-8", "sequence": "1", "secsgml_size_bytes": 11190}]
{"company-data": {"conformed-name": "IRON MOUNTAIN INC /DE", "cik": "0001004317", "assigned-sic": "4220", "irs-number": "043107342", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-33191", "film-number": "97654231"}, "business-address": {"street1": "745 ATLANTIC AVE", "city": "BOSTON", "state": "MA", "zip": "02111", "phone": "6173574455"}, "mail-address": {"street1": "745 ATLANTIC AVENUE", "street2": "7TH FLOOR", "city": "BOSTON", "state": "MA", "zip": "02111"}}
As filed with the Securities and Exchange Commission on August 8, 1997
                                                       Registration No.

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                 --------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                  ------------

                           IRON MOUNTAIN INCORPORATED
               (Exact name of issuer as specified in its charter)

         Delaware                                  04-3107342
 (State or other jurisdiction of                (I.R.S. Employer
incorporation or organization)                 Identification No.)

                745 Atlantic Avenue, Boston, Massachusetts 02111
                                 (617) 357-4455
           (Address of Principal Executive Offices including zip code)
                                  -------------

              Iron Mountain Incorporated 1995 Stock Incentive Plan
                            (Full titles of the plan)
                                  ------------

                                C. Richard Reese
                            Chairman of The Board of
                      Directors and Chief Executive Officer
                           Iron Mountain Incorporated
                               745 Atlantic Avenue
                           Boston, Massachusetts 02111
                                 (617) 357-4455
            (Name, address and telephone number of agent for service)
                                  -------------

                                    Copy to:
                             William J. Curry, Esq.
                            Sullivan & Worcester LLP
                             One Post Office Square
                           Boston, Massachusetts 02109
                                 (617) 338-2800
                                ----------------

The prospectus  meeting the  requirements of Section 10(a) of the Securities Act
of 1933, as amended,  which is being provided to  participants in the 1995 Stock
Incentive Plan in conjunction with this  Registration  Statement also relates to
the shares  registered under the Registration  Statement on Form S-8 dated April
9, 1997 (File No. 333-24803) of Iron Mountain Incorporated.
---------------

                                          CALCULATION OF REGISTRATION FEE

                                                        Proposed            Proposed Maximum
  Title of Securities         Amount to be          Maximum Offering            Aggregate                  Amount of
   to be Registered            Registered          Price Per Share(1)       Offering Price(1)           Registration Fee
   ----------------            ----------          ------------------       -----------------           ----------------
Common Stock, par
value $.01 per share             400,000                 $31.375               $12,550,000               $3,803.03
(1)      With respect to the additional  400,000 shares  issuable under the 1995
         Stock Incentive Plan, the proposed maximum offering price per share and
         the  proposed  maximum  aggregate  offering  price have been  estimated
         solely for purpose of calculating the amount of the registration fee in
         accordance  with Rules  457(c) and 457(h) under the  Securities  Act of
         1933,  as  amended,  on the  basis of the  average  of the high and low
         prices of the Common  Stock on the Nasdaq  National Market on August 6,
         1997.  944,903 shares issuable under the 1995 Stock Incentive Plan were
         registered  under the Registrant's  registration  statement on Form S-8
         (File No.  333-24803),  filed  with  Commission  on April 9, 1997 and a
         filing  fee of  $4,425.28  was paid on such date with  respect  to such
         shares.
PART II - INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

         Insofar as additional securities are being registered of the same class
as other  securities  for  which a  registration  statement  filed on this  form
relating to an employee  benefit plan is effective,  in accordance  with General
Instruction  E  to  the  Registration  Statement  on  Form  S-8,  Iron  Mountain
Incorporated  (the "Company")  hereby  incorporates by reference the contents of
the Company's  Registration  Statement on Form S-8 dated April 9, 1997 (File No.
333-24803) and omits the information  required by Part II from this Registration
Statement, other than Item 3 and Item 8, below, which have been updated.

Item 3.  Incorporation of Documents by Reference.

         The Company previously registered under the Securities Act an aggregate
of 944,903 shares of Common Stock offered  pursuant to the 1995 Stock  Incentive
Plan pursuant to a Registration  Statement on Form S-8 (File No. 333-2196) filed
with the Commission on April 9, 1997, which is incorporated in this Registration
Statement by reference.

         The  following  additional  documents,  which  have  been  filed by the
Company with the Commission, are incorporated by reference in and made a part of
this Registration Statement, as of their respective dates:

          (a)  The  Company's  Annual  Report on Form 10-K for the  fiscal  year
               ended December 31, 1996;

          (b)  The Company's Quarterly Report on Form 10-Q for the quarter ended
               March 31, 1997;

          (c)  The Company's Current Report on Form 8-K dated June 12, 1997; and

          (d)  The  description  of the Common Stock  contained in the Company's
               registration  statement on Form 8-A dated  January 18, 1996 (File
               No.  0-27584),  including any amendments or reports filed for the
               purpose of updating such description.

         All documents  subsequently  filed by the Company  pursuant to Sections
13(a),  13(c), 14 and 15(d) of the Securities  Exchange Act of 1934, as amended,
prior to the  filing of a  post-effective  amendment  which  indicates  that all
securities  offered  have been sold or which  deregisters  all  securities  then
remaining  unsold,  shall be  deemed to be  incorporated  by  reference  in this
Registration  Statement  and to be part  hereof  from the date of filing of such
documents.

         Any  statement  contained  in a document  incorporated  or deemed to be
incorporated  by reference  herein shall be deemed to be modified or  superseded
for  purposes  of this  Registration  Statement  to the extent  that a statement
herein,  or in any subsequently  filed document which also is or is deemed to be
incorporated by reference,  modifies or supersedes such statement. Any statement
so  modified  or  superseded  shall  not be  deemed,  except as so  modified  or
superseded, to constitute a part of this Registration Statement.

Item 8.  Exhibits.
                                   EXHIBIT INDEX

              Exhibit No.       Description

                  5        Opinion of Sullivan & Worcester LLP.*

                  23.1     Consent of Sullivan & Worcester LLP (contained in the
                           opinion of Sullivan & Worcester LLP filed herewith as
                           Exhibit 5).

                  23.2     Consent of Arthur Andersen LLP.*

                  24       Power of Attorney (included in signature page of this
                           Registration Statement).

*Filed herewith.

                                     II - 1
SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, the Company
certifies  that it has  reasonable  grounds to believe  that it meets all of the
requirements  for  filing  on Form S-8 and has  duly  caused  this  Registration
Statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized, in the City of Boston, Commonwealth of Massachusetts, on the 8th day
of August, 1997.

                                     IRON MOUNTAIN INCORPORATED

                                     By: /s/ C. Richard Reese
                                          C. Richard Reese
                                          Chairman of the Board,
                                          Chief Executive Officer and Director

         The  undersigned  Officers and Directors of Iron Mountain  Incorporated
(the "Company") hereby severally constitute C. Richard Reese, John F. Kenny, Jr.
and  David S.  Wendell,  and each of them  acting  singly,  our true and  lawful
attorneys to sign for us and in our names in the capacities  indicated below any
amendments  to  this   Registration   Statement  on  Form  S-8   (including  any
post-effective  amendments  hereto) and to file the same, with Exhibits  thereto
and other  documents in connection  therewith,  with the Securities and Exchange
Commission,  granting unto each of said attorneys, acting singly, full power and
authority to do and perform each and every act and thing  requisite or necessary
to be done in and about the premises, as fully to all intents and purposes as he
might or could do in person,  hereby  ratifying and confirming our signatures to
said amendments to this Registration  Statement signed by our said attorneys and
all else  that said  attorneys  may  lawfully  do and cause to be done by virtue
hereof.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement has been signed below by the following persons on behalf
of the Company and in the capacities and on the 8th day of August, 1997.

     Signatures                             Title

       /s/ C. Richard Reese
     C. Richard Reese                  Chairman, Chief
                                       Executive Officer and Director

       /s/ David S. Wendell
     David S. Wendell                  President, Chief Operating Officer and
                                       Director

       /s/ John F. Kenny
     John F. Kenny, Jr.                Executive Vice President and
                                       Chief Financial Officer

       /s/ Eugene B. Doggett
     Eugene B. Doggett                 Executive Vice President and Director

                                     II - 2
Constantin R. Boden               Director

     Arthur D. Little                  Director

       /s/ Vincent J. Ryan
     Vincent J. Ryan                   Director

       /s/ B. Thomas Golisano
     B. Thomas Golisano                Director

       /s/ Jean A. Bua
     Jean A. Bua                       Vice President and Corporate
                                       Controller

                                     II - 3