Exhibit 21 SUBSIDIARIES OF CASS INFORMATION SYSTEMS, INC. Name & Address State of Incorporation - -------------- ---------------------- Cass Commercial Bank Missouri 13001 Hollenberg Drive Bridgeton, Missouri 63044 Cass Information Systems, Inc. Missouri 13001 Hollenberg Drive Bridgeton, Missouri 63044 Government e-Management Solutions, Inc. Missouri 121 Hunter Avenue Suite 100 St. Louis, MO 63124