EXHIBIT 21.1 MRO SOFTWARE, INC. List of Subsidiaries Jurisdiction of Name of Subsidiary Incorporation Ownership - ------------------ --------------- --------- MRO International Software, Inc. Delaware (1) MRO Security Corporation Massachusetts (1) MRO International Holdings, Inc. Delaware (2) MRO Software, UK Limited United Kingdom (2) MRO Software (Canada) Limited Canada (2) MRO Software S.A.R.L. France (2) MRO Software Australia Pty. Limited Australia (2) MRO Software GmbH Germany (2) MRO Software NV Netherlands (2) MRO Software AB Sweden (2) MRO Software Japan K.K. Japan (2) MRO Software (Thailand) Limited Thailand (2) MRO Software India Private Limited India (2) MRO Software do Brasil Ltda. Brazil (3) MRO Software Hong Kong Ltd. Hong Kong (2) MRO Software Mexico S.A. de C.V. Mexico (2) MRO Software (Shanghai) Co. Ltd China (1) MRO Software Italia s.r.l. Italy (2) MRO.com, Inc. Delaware (1) MRO.com, Limited United Kingdom (4) MRO.com, Limited Canada (4) MRO.com Pty Limited Australia (4) MRO.com (Asia) Limited Hong Kong (4) INTERMAT, Inc. Delaware (1) MainControl, Inc. Delaware (5) MC Holding Corp. I Delaware (1) MC Holding Corp II Delaware (1) MC Holding Corp. III Delaware (5) MainControl Research Ltd. Delaware (6) MainControl (UK) Limited United Kingdom (6) MainControl GmbH Germany (6) MainControl, Ltd. Israel (6&7) MainControl Research Ltd Delaware (6&7) IDFM, Inc. Massachusetts (1) Applied Image Technology, Inc. Michigan (1) Modern Distribution Management, Inc. Minnesota (4) (1) All of the outstanding capital stock is owned by MRO Software, Inc. (2) All of the outstanding capital stock (other than certain qualifying shares required in the jurisdiction of organization and representing from 0% to 2% of the outstanding capital stock), is owned by MRO International Software, Inc. (3) 4,950 shares are owned by MRO International Software, Inc. and 50 shares are owned by MRO International Holdings, Inc. (4) All outstanding capital stock is owned by MRO.com, Inc. (5) MRO Software Inc. owns 100% of MC Holding Corp. I and MC Holding Corp. II. MRO Holding Corp. I and MC Holding Corp. II each hold a 50% interest in MC Holding Corp. III. MC Holding Corp. III owns 100% of MainControl, Inc. MC Page 74 Holding Corp. III originally owned 100% of Capri Acquisition Corp. which was merged into MainControl, Inc. (6) MainControl, Inc owns 100%. (7) MainControl, Ltd. Israel (The Company holds 3,999 shares and 1 share is held by G.L.E. Trust Services Ltd.) also domesticated in Delaware for tax purposes as MainControl Research Ltd. Page 75