The 720 study subjects who underwent retrospective interviews consisted of male and female methadone maintenance patients selected from several California clinics. The independent variable in the study was legal supervision; the dependent variables consisted of drug use, criminal behavior, social functioning, and treatment. The results indicate that legal supervision is effective in controlling the behavior of chronic narcotics addicts from all four gender and ethnic combinations. Differences found included that male Chicanos decreased their drug use to a level lower than white males and Chicano females to a level higher than white females during the first legal supervision. Both Chicano groups showed a greater rebound between first and second legal supervision than whites; at the second legal supervision, whites responded better than Chicanos. The opposite effects appeared in the incidence of property crime. While Chicanos reduced the percentage of time committing crime in response to legal supervision, whites rebounded after first legal supervision and then reduced their percentage of time committing crime to lower levels than Chicanos at second level supervision. Greater gains appear to be made in controlling these behaviors when supervision is combined with methadone treatment. 6 tables, 18 figures, and 47 references.