QuickLinks -- Click here to rapidly navigate through this document

Exhibit 99.1

FOR IMMEDIATE RELEASE:

Contact: Stephen P. Golden
Director of Investor Relations
(617) 535-4799

Iron Mountain Incorporated Announces Proposed GBP 125 Million
Senior Subordinated Notes Offering

Boston, MA—January 7, 2004—Iron Mountain Incorporated (NYSE: IRM), the leader in records and information management services, announced today a proposed offering of GBP 125 million in aggregate principal amount of its Senior Subordinated Notes due 2014. The Company intends to use the net proceeds from the offering to fund the previously announced acquisition of Mentmore plc's 49.9% equity interest in Iron Mountain Europe Limited for total consideration of GBP 82.5 million, which includes the related repayment of trade and working capital funding owed to Mentmore by Iron Mountain Europe, and for general corporate purposes, including the possible repayment of outstanding borrowings under its revolving credit facility, the possible repayment of other indebtedness and possible future acquisitions and investments. The exact terms and timing of the offering will depend upon market conditions and other factors.

The notes are being sold only to qualified institutional buyers under Rule 144A and to persons outside the United States under Regulation S. The notes have not been registered under the Securities Act of 1933 or under the securities laws of any other jurisdiction, and, unless so registered under the Securities Act of 1933, may not be offered or sold in the United States except pursuant to an exemption from, or in a transaction not subject to, the registration requirements of the Securities Act and applicable state securities laws. This press release does not constitute an offer, offer to sell, or solicitation of an offer to buy any securities in any jurisdiction in which such offering, solicitation or sale would be unlawful.

Stabilisation/FSA

About Iron Mountain

Iron Mountain Incorporated is the world's trusted partner for outsourced records and information management services. Founded in 1951, the Company has grown to service more than 150,000 customer accounts throughout the United States, Canada, Europe and Latin America. Iron Mountain offers records management services for both physical and digital media, disaster recovery support services and consulting services—services that help businesses save money and manage risks associated with legal and regulatory compliance, protection of vital information, and business continuity challenges. For more information, visit www.ironmountain.com.

QuickLinks

Exhibit 99.1

Iron Mountain Incorporated Announces Proposed GBP 125 Million Senior Subordinated Notes Offering