Cocaine dependence/abuse has proven to be difficult to treat successfully. Cognitive-behavioral therapy (CBT), often referred to as relapse prevention in the addiction treatment field, uses social learning principles in teaching patients to recognize and cope with high-risk situations that maintain drug use or precipitate relapse. During the first, intensive phase of the enhanced intervention in this study, CPT therapists served as the patients’ methadone counselors. During the second, lower intensity phase of the intervention, CBT therapy groups were conducted by regular methadone counselors that received training and clinical supervision from the study staff. Eligible patients were recruited between November 1995 and September 1995 at four methadone clinics operated by the Beth Israel Medical Center in New York City. Two of these four methadone clinics were randomly designated as enhanced treatment sites and the remaining two as standard treatment sites. Results show that cocaine-using methadone patients that received either enhanced or standard methadone treatment and remained in methadone treatment for at least 9 weeks reported significant but equivalent declines in cocaine use over the 12-month study period. Enhanced treatment, consisting of cognitive-behavioral individual and group sessions and incentives for completing treatment-related tasks, was satisfactorily implemented. The enhanced treatment patients attended a substantial number of sessions and the majority of them completed the 4 month intensive phase. Subjects assigned to enhanced treatment rated the quality of the therapeutic relationship higher than those subjects receiving standard methadone treatment. They were also more likely to have obtained medical services, psychiatric services, and public assistance benefits. The findings indicate that methadone maintenance treatment can help dually addicted patients reduce their cocaine use. 3 tables, 52 references