This study examined outcomes and their predictors among 181 probationers enrolling in opioid agonist maintenance with methadone or levo-alpha-acetylmethadol (LAAM). Participants were interviewed at treatment entry and 2-, 6-, and 12-month follow-ups. Treatment retention and frequency of heroin use, cocaine use, and income-generating criminal activity were examined using survival and longitudinal analyses. Participants reported marked reductions in drug use and crime relative to treatment entry. A number of patient characteristics associated with various outcomes were identified. The findings support engaging probationers in treatment and highlight patient factors that might influence outcomes.