This study compared the efficacy of 2 approaches for the treatment of cocaine dependence among methadone-maintained patients with and without antisocial personality disorder (ASPD). Patients were randomly assigned to 4 study conditions: cognitive-behavioral treatment (CBT), contingency management (CM), CBT with CM, or methadone maintenance. The Structural Clinical Interview for Mental Disorders-IV was administered to 108 patients to assess ASPD. A 2-way analysis of variance showed that patients with ASPD were more likely to abstain from cocaine use during treatment than patients without ASPD. The strong treatment effect for ASPD patients was primarily due to the CM condition. Regression analyses showed that ASPD remained significantly related to CM treatment responsivity while controlling for other factors.