EXHIBIT 21.1



LIST OF SUBSIDIARIES



|                                                                                     |  |                       
|------------------------------------------------------------------------------------ |  | ----------------------
|NAME                                                                                 |  | STATE OF INCORPORATION
|Concentra Akron, L.L.C.                                                              |  | Delaware              
|Concentra Arkansas, L.L.C. (d/b/a Concentra Medical Centers)                         |  | Delaware              
|Concentra Birmingham, L.L.C. (d/b/a Concentra Medical Centers)                       |  | Delaware              
|Concentra Health Services, Inc. (d/b/a Concentra Medical Centers)                    |  | Nevada                
|Concentra Integrated Services, Inc. (d/b/a Concentra Medical Examinations)           |  | Massachusetts         
|Concentra Laboratory, L.L.C. (d/b/a Advanced Toxicology Network)                     |  | Delaware              
|Concentra Managed Care Business Trust                                                |  | Massachusetts         
|Concentra Management Services, Inc.                                                  |  | Nevada                
|Concentra New Orleans, L.L.C. (d/b/a Concentra Medical Centers)                      |  | Delaware              
|Concentra Occupational Healthcare Harrisburg, L.P. (d/b/a Concentra Medical Centers) |  | Pennsylvania          
|Concentra Preferred Business Trust                                                   |  | Massachusetts         
|Concentra Preferred Systems, Inc.                                                    |  | Delaware              
|Concentra South Carolina, L.L.C. (d/b/a Concentra Medical Centers)                   |  | Delaware              
|Concentra St. Louis, L.L.C. (d/b/a Concentra Medical Centers)                        |  | Delaware              
|Concentra Vanderbilt, L.L.C. (d/b/a Concentra Medical Centers)                       |  | Delaware              
|Concentra Winston-Salem, L.L.C. (d/b/a Concentra Medical Centers)                    |  | Delaware              
|Concentra-UPMC, L.L.C (d/b/a Concentra Medical Centers)                              |  | Delaware              
|CRA Managed Care of Washington, Inc. (d/b/a Concentra Integrated Services)           |  | Washington            
|CRA-MCO, Inc.                                                                        |  | Nevada                
|First Notice Systems, Inc.                                                           |  | Delaware              
|Focus Healthcare Business Trust                                                      |  | Massachusetts         
|Focus Healthcare Management, Inc. (d/b/a Concentra Network Services)                 |  | Tennessee             
|HealthNetwork Systems LLC                                                            |  | Delaware              
|Managed Prescription Program Joint Venture                                           |  | Arizona               
|Medical Network Systems LLC                                                          |  | Delaware              
|MetraComp, Inc.                                                                      |  | Connecticut           
|National Healthcare Resources, Inc.                                                  |  | Delaware              
|NHR Washington, Inc.                                                                 |  | Delaware              
|OccuCenters I, L.P. (d/b/a Concentra Medical Centers; Concentra)                     |  | Texas                 
|Occupational Health Ventures, L.L.C (d/b/a Concentra Medical Centers)                |  | Pennsylvania          
|OCI Holdings, Inc.(d/b/a Concentra Medical Centers)                                  |  | Nevada                
|OHC of Oklahoma, L.L.C. (d/b/a Concentra Medical Centers)                            |  | Oklahoma              
|OnSite OccMed, P.A.                                                                  |  | Texas                 
|Tucson Occupational Medicine Partnership (d/b/a Concentra Medical Centers)           |  | Arizona