Abstinence at successful discharge in substance use disorder treatment is important to reducing relapse rates and increasing long-term recovery from substance use disorders. However, few studies have examined abstinence as an essential component of successful discharge. This study examined rates and correlates of reported abstinence (nonuse of drugs 30 days prior to successful discharge) among clients attending publicly funded treatment in Los Angeles County, California. Finding show that only 36% of clients who were successfully discharged reported abstinence. Black clients were less likely than non-Hispanic Whites to report abstinence at successful discharge. Clients in methadone treatment programs were less likely than outpatient clients to report abstinence, whereas clients referred to treatment through the legal system (Proposition 36) were more likely to report abstinence compared to self-referred clients. Findings underscore the importance of systematic assessment of abstinence in determining successful discharge and provide a basis for further examination of strategies to improve abstinence and reduce relapse.