MILLER BUILDING SYSTEMS, INC. EXHIBIT 21 SUBSIDIARIES OF THE REGISTRANT JULY 1, 2000 The subsidiaries of the Registrant are as follows: Percentage of Voting Name Incorporated Securities Owned by Under Law Of: Immediate Parent Miller Building Systems of Indiana, Inc. Indiana 100% Miller Building Systems of Pennsylvania, Inc. Indiana 100% Miller Building Systems of Kansas, Inc. Kansas 100% (2) Miller Building Systems of South Dakota, Inc. South Dakota 100% (1) Miller Construction Services, Inc. Indiana 100% United Structures, Inc. New York 100% PME Pacific Systems, Inc. California 100% (2) (1) Wholly-owned subsidiary of Miller Building Systems of Kansas, Inc. (2) Inactive Corporation.