PRIMARY PROGRAM EMPHASIS WAS PLACED ON MEASURING ITS IMPACT ON DISPOSITIONS AND OVERALL CRIMINAL JUSTICE SYSTEM PROCESSING (INCLUDING SENTENCES) AND ITS IMPACT ON RECIDIVISM RATES AND ASSOCIATED PROCESSING. DOLLAR FIGURES WERE ASSIGNED TO THE VARIOUS EVENTS AND PROCESSES ASSOCIATED WITH THE IMPACTS. THE BASIS FOR ASSESSING PROGRAM IMPACT AND COST EFFECTIVENESS WAS A COMPARISON BETWEEN SAMPLES OF PROGRAM PARTICIPANTS AND MATCHED SAMPLES OF NONPARTICIPANTS. CLIENTS RECEIVING SERVICES (OFFICIAL CLIENTS) TOTALED 137; CLIENTS IN THE PROGRAM BUT NOT RECEIVING SERVICES (THOSE INTERVIEWED BY DIVERSION STAFF AND FOR WHOM RECOMMENDATIONS WERE MADE TO THE COURT) NUMBERED 35. THE COMPARISON SAMPLE FOR CLIENTS RECEIVING SERVICES WAS 137 PERSONS AND FOR CLIENTS NOT RECEIVING SERVICES WAS 32 PERSONS. DEFENDANTS WERE EVALUATED IN TERMS OF AGE, SEX, RACE/ETHNICITY, COURT OF ARRAIGNMENT, CHARGE OR OFFENSE, AND PREVIOUS ADULT RECORD. PROGRAM IMPACT WAS EVALUATED ON THE BASIS OF PROGRESS IN VARIOUS TYPES OF SOCIAL OR BEHAVIORAL PROBLEM RESOLUTION. COST EFFECTIVENESS ANALYSIS EXAMINED WHETHER THE DIVERSION OF CASES TO THE PROGRAM REDUCED COSTS TO THE CRIMINAL JUSTICE SYSTEM, REDUCED FUTURE COSTS AS A RESULT OF REDUCED RECIDIVISM RATES, AND REDUCED PUBLIC ASSISTANCE EXPENDITURES AS A RESULT OF HELPING REMOVE PEOPLE FROM PUBLIC ASSISTANCE ROLLS. THE PRETRIAL DIVERSION PROGRAM HAD SIGNIFICANT IMPACTS IN THE FOLLOWING AREAS: REDUCTION IN CONVICTIONS ON ORIGINAL CHARGES, REDUCTION IN THE NUMBER OF PEOPLE REARRESTED AND IN THE TOTAL NUMBER OF SUBSEQUENT ARRESTS, REDUCTION IN SUBSEQUENT CONVICTIONS, AND REDUCTION IN JAIL AND PROBATION TIME SERVED. THE PROGRAM WAS COST EFFECTIVE. SUPPORTING DATA ARE PROVIDED.