WASHINGTON, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT
                       Pursuant to Section 13 or 15(d) of
                       The Securities Exchange Act of 1934

       Date of Report (Date of earliest event reported): December 10, 2003

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

                 (State or other jurisdiction of incorporation)

         1-13045                                          23-2588479
(Commission File Number)                       (IRS Employer Identification No.)

                               745 Atlantic Avenue
                           Boston, Massachusetts 02111
          (Address of principal executive offices, including zip code)

                                 (617) 535-4766
              (Registrant's telephone number, including area code)

Item 5. Other Events and Regulation FD Disclosure

On December 10, 2003, the Company issued a press release announcing that it
signed an agreement with Mentmore plc to acquire Mentmore's 49.9% equity
interest in Iron Mountain Europe Limited. Completion of this transaction will
give Iron Mountain 100% ownership of Iron Mountain Europe Limited. A copy of the
Company's press release is attached hereto as Exhibit 99.1 and is incorporated
herein by reference.

Item 7. Financial Statements and Exhibits

(c) Exhibits.

Exhibit No.       Item
-----------       ----
99.1              Press release dated December 10, 2003.


Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.

                               IRON MOUNTAIN INCORPORATED

                               By: /s/ Jean A. Bua
                               Name:  Jean A. Bua
                               Title: Vice President and Corporate Controller

      Date: December 10, 2003