UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             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): April 29, 2004

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

                                  PENNSYLVANIA
                 (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 12. Results of Operations and Financial Condition.

On April 29, 2004, the Company issued a press release setting forth the
Company's results of operations and financial condition for its first fiscal
quarter ended March 31, 2004. A copy of the Company's press release is attached
hereto as Exhibit 99.1 and is incorporated herein by reference.

SIGNATURES

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
                                  (Registrant)

                                  By: /s/ Jean A. Bua
                                     ----------------

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

      Date: April 29, 2004