A HISTORY OF HEROIN ADDICTION AND TREATMENT IS PRESENTED AND 10 STUDIES EVALUATING THE EFFECTIVENESS OF METHADONE TREATMENT IN REDUCING CRIMINAL BEHAVIOR ARE REVIEWED. THE KEYWAY PROGRAM OF ROCKFORD, ILL., WAS EVALUATED. THE STUDY SAMPLE WAS DIVIDED INTO 4 GROUPS: (1) CLIENTS WITH NO CRIMINAL RECORDS, (2) CLIENTS WITH MISDEMEANOR CONVICTIONS, (3) CLIENTS WITH FELONY CONVICTIONS, AND (4) CLIENTS WITH MISDEMEANOR AND FELONY CONVICTIONS. TO DISCERN THE PROPORTION OF INDIVIDUALS WHOSE BEHAVIOR CHANGED IN ONE DIRECTION AS OPPOSED TO ANOTHER, THE SIGN TEST WAS EMPLOYED TO DETERMINE PRETREATMENT AND TREATMENT INDICATORS OF CRIMINAL ACTIVITY. RESULTS SHOWED THAT 48 CLIENTS IMPROVED THEIR RECORD DURING AND AFTER TREATMENT, 47 INCREASED CRIMINAL BEHAVIOR, AND 79 REMAINED THE SAME. FINDINGS ARE DETAILED FOR THE CLIENT GROUPS AND A DESCRIPTION OF PROGRAM RETENTION RATES IS PROVIDED. IT IS CONCLUDED THE KEYWAY TREATMENT DOES NOT AFFECT CRIMINAL BEHAVIOR. IT IS NOTED THAT THIS EVALUATION STUDY OF KEYWAY'S METHADONE TREATMENT PROGRAM DOES NOT CONFORM TO THE PATTERNS OF PUBLISHED REPORTS ON OTHER METHADONE CENTERS. THE DATA COLLECTION INSTRUMENT IS APPENDED, AND SUPPORTING DATA AND A BIBLIOGRAPHY ARE PROVIDED. (DAG)