EXHIBIT 21 HEALTH MANAGEMENT SYSTEMS, INC. LIST OF SUBSIDIARIES <Table> <Caption> STATE OF SUBSIDIARY INCORPORATION - ---------- ------------- Accelerated Claims Processing, Inc.......................... Delaware 401 Park Avenue South New York, NY 10016 Health Receivables Management, Inc.......................... Delaware 820 West Jackson Boulevard, Suite 725 Chicago, IL 60607 HSA Managed Care Systems, Inc............................... Delaware 234 Spring Lake Drive Itasca, IL 60143-3203 Quality Medi-Cal Adjudication, Incorporated................. California 10381 Old Placerville Road Sacramento, CA 95827 (Sold substantially all assets on January 1, 2001 see Note 16 of the Notes to Consolidated Financial Statements) CDR Associates, Inc......................................... Maryland 9642 Deereco Road Timonium, MD 21093 (Sold substantially all assets on June 30, 2001 see Note 16 of the Notes to Consolidated Financial Statements) SUBSIDIARIES SOLD DURING THE YEAR ENDED DECEMBER 31, 2001 Health Care Microsystems, Inc............................... California 200 North Sepulveda Boulevard, Suite 600 El Segundo, CA 90245 (Sold subsidiary on December 11, 2001, see Note 16 of the Notes to Consolidated Financial Statements) </Table>