Exhibit No. 21 HARDING LAWSON ASSOCIATES GROUP, INC. SUBSIDIARIES OF THE REGISTRANT State or Name Country of Incorporation Doing Business Under Harding Lawson Associates, Inc. Delaware Harding Lawson Associates, Inc. Harding Lawson Associates Delaware Harding Lawson Associates Infrastructure, Inc. Infrastructure, Inc. Harding Lawson Associates Delaware Harding Lawson Associates International, Inc. (formerly International, Inc. Harding International, Inc.) Harding Lawson Australia, Pty. Ltd. New South Harding Lawson Australia, Pty. (wholly owned subsidiary of Wales, Ltd. Harding Lawson Associates Australia International, Inc.) HLA-Envirosciences Pty Limited New South HLA-Envirosciences Pty Limited (majority owned subsidiary of Wales, Harding Lawson Australia, Australia Pty. Ltd.) Harding Lawson de Mexico S.A. City of Harding Lawson de Mexico S.A. de C.V. (wholly owned subsidiary Mexico, de C.V. Harding Lawson Associates Federal International, Inc.) District Grupo Industrial de Ingenieria City of GRIECO Ecologica III, HLA & Iconsa S.A. Mexico, de C.V. (majority owned subsidiary Federal of Harding Lawson de Mexico S.A District de C.V.) Harding Lawson Singapore Pte Ltd Singapore Harding Lawson Singapore Pte Ltd HLA Venture, Inc. Delaware HLA Venture, Inc. Harding Construction Services, Delaware (Dormant) Inc. Redwood Company, Ltd. Bermuda (Dormant) Redwood Insurance, Ltd. Bermuda (Dormant) (wholly owned subsidiary of Redwood Company, Ltd.) Integrated Software Systems, LLC Colorado Integrated Software Systems, (Harding Lawson Associates, Inc. LLC has a minority interest in LLC)