Aims. To evaluate disulfiram and three forms of manual guided psychotherapy for individuals with cocaine dependence and concurrent alcohol abuse or dependence. Design. Randomized controlled trial. Setting. Urban substance abuse treatment center. Participants. One hundred and twenty-two cocaine/alcohol abusers (27% female; 61% African-American or Hispanic). Interventions. One of five treatments delivered over 12 weeks: cognitive behavioral treatment (CBT) plus disulfiram; Twelve Step facilitation (TSF) plus disulfiram; clinical management (CM) plus disulfiram; CBT plus no medication; TSF plus no medication. Measurements. Duration of continuous abstinence from cocaine or alcohol; frequency and quantity of cocaine and alcohol use by week, verified by urine toxicology and breathalyzer screens. Findings. Disulfiram treatment was associated with significantly better retention in treatment, as well as longer duration of abstinence from alcohol and cocaine use. The two active psychotherapies (CBT and TSF) were associated with reduced cocaine use over time compared with supportive psychotherapy (CM). Cocaine and alcohol use were strongly related throughout treatment, particularly for subjects treated with disulfiram. Conclusions. For the large proportion of cocaine-dependent individuals who also abuse alcohol, disulfiram combined with outpatient psychotherapy may be a promising treatment strategy. This study underlines (a) the significance of alcohol use among treatment-seeking cocaine abusers, (b) the promise of the strategy of treating co-morbid disorders among drug-dependent individuals, and (c) the importance of combining psychotherapy and pharmacotherapy in the treatment of drug use disorders.