The employment patterns of 342 male methadone maintenance patients who remained in treatment for at least 1 year are examined. Four periods in the patients' lives are considered: (1) the period before addiction, (2) the period of addiction, (3) the time of entry into the treatment program, and (4) the first treatment year. Although more than three-quarters of the patients were employed regularly during the period before addiction, only about one-quarter were employed while addicted. At entry into the program 15% were employed, and 25% worked regularly during the first treatment year. An examination of some demographic, social, and work-related correlates of employment status during each period revealed that factors such as ethnicity, educational attainment, marital status, alcohol use, previous employment, and attitudes toward work were all important in relation to patients' employment status at one or more of the four periods. The treatment program had only a moderate impact on patients' attitudes toward work and employment behavior.