EXHIBIT 21 



                      LIST OF SUBSIDIARIES OF REGISTRANT 



Subsidiary of Registrant 



 1. Iron Mountain Records Management, Inc. 
    State of incorporation -- Delaware 
    In California, also does business as Metro Records Management 



Subsidiaries of Iron Mountain Records Management, Inc. 


 1. Metro Business Archives, Inc. 
    State of incorporation -- New York 
    Doing business as Metro Business Archives 

 2. Criterion Atlantic Property, Inc. 
    State of incorporation -- Delaware 

 3. Criterion Property, Inc. 
    State of incorporation -- Delaware 

 4. Hollywood Property, Inc. 
    State of incorportion -- California 

 5. IM San Diego, Inc. 
    State of incorporation -- Delaware 

 6. Iron Mountain Information Partners, Inc. 
    State of incorporation -- Delaware 

 7. Iron Mountain Data Protection Services, Inc. 
    State of incorporation -- Massachusetts 

 8. Iron Mountain Records Management of Maryland, Inc. 
    State of incorporation -- Delaware 

 9. Iron Mountain Records Management of Ohio, Inc. 
    State of incorporation -- Delaware 

10. Iron Mountain Wilmington, Inc. 
    State of incorporation -- Delaware 

11. Data Storage Systems, Inc. 
    State of incorporation -- Delaware 

12. Iron Mountain Records Management of Missouri LLC 
    State of organization -- Delaware 

13. Iron Mountain Records Management of Boston, Inc. 
    State of incorporation -- Massachusetts 

14. Data Archive Services, Inc. 
    State of incorporation -- Delaware