Alcoholism is a frequent complication of methadone treatment. In this study, the reinforcing properties of methadone were employed therapeutically to maintain patients on disulfiram. In the experimental condition, alcoholic methadone patients were given methadone only if they also ingested disulfiram. In the control situation, patients with the same addictions were given disulfiram but were not required to ingest it as a condition of receiving methadone. The results indicated that alcoholism was effectively arrested only while patients were treated under the experimental condition.