Analyses examined whether addicts reporting themselves coerced into drug abuse treatment by actions of the criminal justice system differed from voluntary admissions in their response to treatment, and whether such responsiveness varied across gender or ethnicity. Six hundred eighteen methadone maintenance clients admitted to programs in six southern California counties were categorized into high, moderate, and low legal coercion levels. Multivariate analysis of variance procedures for repeated measures (before, during, and after initial treatment episode) were used to test relevant hypotheses. Dependent variables included criminal justice system contact, criminal activities, drug and alcohol involvement, and measures of social functioning. Few differences within any measured domain were found among the three groups. All groups were similar in showing substantial improvement in levels of narcotics use, criminal activities, and most other behaviors during treatment with some regression in these behaviors posttreatment. Results support legal coercion as a valid motivation for treatment entry; those coerced into treatment respond in ways similar to voluntary admissions regardless of gender or ethnicity.