Exhibit 21

### The Titan Corporationand Its SubsidiariesAs of March 26, 2002

|Name                                                    | Subsidiary of:                            | State or Jurisdiction of Incorporation
|------------------------------------------------------- | ----------------------------------------- | --------------------------------------
|                                                        |                                           |                                       
|ACS Technologies, Inc.                                  | Advanced Communications Systems, Inc.     | Virginia                              
|Advanced Communications Systems, Inc.                   | The Titan Corporation                     | Delaware                              
|Advanced Management, Inc.                               | Advanced Communications Systems, Inc.     | Virginia                              
|Assist Cornerstone Technologies, Inc.                   | Cayenta, Inc. & Cayenta Operating Company | Utah                                  
|Atlantic Aerospace Electronics Corporation              | The Titan Corporation                     | Delaware                              
|AverCom Corporation                                     | The Titan Corporation                     | Delaware                              
|BTG Systems Engineering, Inc.                           | BTG, Inc.                                 | Virginia                              
|BTG Technology Resources, Inc.                          | BTG, Inc.                                 | Florida                               
|BTG Technology Systems, Inc.                            | BTG, Inc.                                 | Virginia                              
|BTG, Inc.                                               | The Titan Corporation                     | Virginia                              
|Cayenta Canada, Inc.                                    | Cayenta, Inc.                             | Canada                                
|Cayenta eUtility Solutions - eMunicipal Solutions, Inc. | Cayenta Canada, Inc.                      | Nevada                                
|Cayenta Operating Company                               | Cayenta, Inc.                             | Delaware                              
|Cayenta, Inc.                                           | The Titan Corporation                     | Delaware                              
|Concept Automation, Inc. of America                     | BTG Technology Resources, Inc.            | Virginia                              
|Datron Advanced Technologies, Inc.                      | Datron Systems Incorporated               | California                            
|Datron Resources, Inc.                                  | Datron Advanced Technologies, Inc.        | California                            
|Datron Systems Incorporated                             | The Titan Corporation                     | Delaware                              
|Datron World Communications, Inc.                       | Datron Systems Incorporated               | California                            
|Datron/Trans World Communications International Ltd     | Datron Systems Incorporated               | US VI                                 
|DBA Systems, Inc.                                       | The Titan Corporation                     | Florida                               
|Delfin Systems                                          | The Titan Corporation                     | California                            
|Delta Research Corporation                              | BTG, Inc.                                 | Virginia                              
|GlobalNet, Inc.                                         | The Titan Corporation                     | Nevada                                
|GlobalNet, International, Inc.                          | GlobalNet, Inc.                           | Delaware                              
|Horizons Services Company                               | Titan Systems Corporaiton                 | Delaware                              
|Integrated Systems Control, Inc.                        | Advanced Communications Systems, Inc.     | Virginia                              
|Intermetrics International, Inc.                        | Titan Systems Corporaiton                 | Massachusetts                         
|Intermetrics Securities, Inc.                           | Titan Systems Corporaiton                 | Massachusetts                         
|J.B. Systems, Inc. d/b/a Mainsaver Corporation          | Cayenta, Inc.                             | California                            
|Jaycor, Inc.                                            | The Titan Corporation                     | California                            
|LinCom Corporation                                      | The Titan Corporation                     | California                            
|LinCom Wireless, Inc.                                   | LinCom Corporation                        | Delaware                              
|Linkabit Wireless Limited                               | Linkabit Wireless, Inc.                   | Cayman Islands                        
|Linkabit Wireless, Inc.                                 | The Titan Corporation                     | Delaware                              
|MergeCo, Inc.                                           | The Titan Corporation                     | Delaware                              
|Microlithics Corporation                                | VisiCom Laboratories, Inc.                | Colorado                              
|MJR Associates, Inc.                                    | Titan Systems Corporaiton                 | Delaware                              
|Nations, Inc.                                           | BTG, Inc.                                 | New Jersey                            
|Program Support Associates, Inc.                        | Advanced Communications Systems, Inc.     | Virginia                              
|Pulse Engineering, Inc.                                 | The Titan Corporation                     | Maryland                              
|Pulse Sciences, Inc.                                    | The Titan Corporation                     | California                            
|Research Planning, Inc.                                 | BTG, Inc.                                 | Virginia                              
|RF Microsystems, Inc.                                   | Advanced Communications Systems, Inc.     | California                            
|SB OperatingCo, Inc.                                    | SureBeam Corporation                      | Delaware                              
|SemCor, Inc.                                            | Advanced Communications Systems, Inc.     | New Jersey                            
|SenCom Corporation                                      | Titan Systems Corporaiton                 | Massachusetts                         
|STAC, Inc.                                              | BTG, Inc.                                 | Virginia                              
|SureBeam Corporation                                    | The Titan Corporation                     | Delaware                              
|Titan Africa, Inc.                                      | Titan Wireless, Inc.                      | Delaware                              
|Titan Food Pasteurization Corp                          | SureBeam Corporation                      | Delaware                              
|Titan Medical Sterilization Corp                        | SureBeam Corporation                      | Delaware                              
|Titan Scan Technologies Corporation                     | The Titan Corporation                     | Delaware                              
|Titan SureBeam Brazil, Inc.                             | SB OperatingCo, Inc.                      | Delaware                              
|Titan Systems Corporation                               | The Titan Corporation                     | Delaware                              
|Titan Systems Solutions UK Ltd                          | VisiCom Laboratories, Inc.                | United Kingdom                        
|Titan Vigil, Inc.                                       | The Titan Corporation                     | Delaware                              
|Titan Wireless, Inc.                                    | The Titan Corporation                     | Delaware                              
|Tomotherapeutics, Inc.                                  | The Titan Corporation                     | Delaware                              
|Unidyne Corporation                                     | The Titan Corporation                     | Delaware                              
|UniVision Technologies, Inc.                            | VisiCom Laboratories, Inc.                | Illinois                              
|VisiCom Laboratories, Inc.                              | The Titan Corporation                     | Delaware