Factors associated with relapse to problematic alcohol or illicit drug use were examined in 104 clients enrolled in treatment programmes for substance disorders. Participants were assessed by retrospective self-report questionnaires to explore the roles of family dysfunction, mood states, primary drug of dependence, demographic variables and various other factors in relation to relapse episodes. Consistent with previous studies, the most commonly cited reason for relapse was negative mood states, followed by external pressure to use, desire for positive mood states, and social/family problems. Reasons for relapse did not differ between clients whose primary drug of dependence was heroin, methamphetamine, or alcohol. Methamphetamine abusers and participants in the drug court programme had the fewest relapses. Co-morbid psychological disorders were most commonly diagnosed in the alcoholic group, followed by the methamphetamine group and the heroin group. General family functioning retrospectively improved from time of last relapse to time of testing. Results are consistent with previous work and suggest that relapse factors are remarkably similar across different types of drug dependence.