Almost all those who receive methadone maintenance treatment have a history of criminality. However, few studies have investigated the rate of arrests and convictions for those treated in a methadone program or expelled from treatment. This study investigated criminality among 331 opiate abusers admitted to Stockholm’s methadone maintenance program (SMMP). It analyzed the rate of arrests and convictions for all methadone patients treated in the program between 1988 and 1992. In addition, arrest and conviction rates for patients expelled from treatment due predominantly to misconduct were analyzed. Information concerning the treatment period, age, sex, and HIV status of all participants was obtained from records of the SMMP run by the Stockholm Addiction Center. Results indicated a significant decline in both arrests and convictions among both sexes during methadone treatment, irrespective of the length of time in treatment. The incidence rate of arrests and convictions was found to be significantly higher for men than for women prior to the methadone treatment, but no differences were observed during treatment. The main reasons for leaving methadone treatment were drug or alcohol abuse, followed by difficulties in following treatment rules. Retention in treatment was associated with a marked reduction in arrests and convictions. The incidence of arrests among both positive and negative HIV status patients were the same during treatment. In summary, the methadone treatment was shown to have a profound positive effect on arrests and convictions, not only for patients remaining in treatment but also for those patients who were expelled from treatment involuntarily. References