Exhibit 21.1 SUBSIDIARIES OF REGISTRANT as of 10/31/98 Percentage of Voting Securities Owned by State of Immediate Name Incorporation Parent - ---- ------------- ---------- ABM Industries Incorporated Delaware Registrant (*) ABM Engineering Services Company California 100% ABM Facility Services Company California 100% ABM Family of Services California 100% ABM Janitorial Services - Northern California California 100% ABM Janitorial Services - Southern California+ California 100% ABM Janitorial Services Co., Ltd. British Columbia 100% Accurate Janitor Service, Inc. + California 100% American Building Maintenance Co. - West California 100% American Building Maintenance Co. of Boston California 100% American Building Maintenance Co. of Georgia California 100% American Building Maintenance Co. of Illinois California 100% American Building Maintenance Co. of New York California 100% American Building Maintenance Co. of Utah+ California 100% American Building Service Company+ California 100% American Plant Protection, Inc. California 100% American Public Services California 100% American Security and Investigative Services, Inc. California 100% ABMI Investigative Services+ California 100% ABMI Security Services, Inc. California 100% American Commercial Security Services, Inc. California 100% Ampco System Parking California 100% Amtech Elevator Services California 100% Amtech Energy Services California 100% Amtech Lighting Services California 100% Amtech Lighting Services of Illinois California 100% Amtech Lighting & Electrical Services. California 100% Amtech Reliable Elevator Company of Texas+ Texas 100% Beehive Parking, Inc. Utah 100% Bonded Maintenance Company Texas 100% Bradford Building Services, Inc. California 100% Canadian Building Maintenance Co., Ltd. British Columbia 100% CommAir Mechanical Services California 100% Commercial Air Conditioning of Northern California, Inc. + California 100% Commercial Property Services, Inc. California 100% Easterday Janitorial Supply Company California 100% Servall Services Inc. Texas 100% Supreme Building Maintenance, Ltd. British Columbia 100% System Parking, Inc. California 100% Towel and Linen Service, Inc.+ California 100% (*) Subsidiary relationship to registrant or to subsidiary parents shown by progressive indentation. + Inactive companies.