OBJECTIVE Early dropout is common in substance abuse treatment settings and may lead to poorer outcomes relative to those completing a full course of treatment. Attempts to identify predictors of dropout have yielded mixed results, highlighting the need for additional research in this area to clarify risk and protective factors to guide intervention and retention efforts. This study evaluated predictors of dropout from psychosocial treatment among opioid-dependent patients on methadone maintenance therapy. METHODS Participants included 78 patients who had failed to respond to at least 4 months of methadone maintenance plus group counseling with clinic substance abuse counselors, and were enrolled in a study of randomized psychosocial treatment in addition to treatment-as-usual. Several factors that have been implicated in previous studies as well as two affective variables (distress intolerance and coping motives for drug use) were examined. RESULTS Results indicated that when controlling for various risk factors, age was the only significant predictor of dropout, with younger patients more likely to discontinue treatment early. CONCLUSIONS This study replicates previous findings in opioid-dependent samples that younger patients are at an increased risk of early treatment dropout. CONCLUSIONS Targeted intervention may be needed to retain young patients in drug abuse treatment.