Alcohol use among methadone maintenance treatment program (MMTP) patients is substantial and a frequent impression is that addicts accelerate their consumption once in MMTP. This study reports an attempt to more clearly define alcohol consumption in opioid dependence as well as changes associated with methadone maintenance therapy. Two-day alcohol consumption (2-day EtOH) data were collected initially and quarterly on participants in a randomized controlled trial of intervention for alcoholism. Blood alcohol levels (BAL) were also determined. 17% of the participants were classified as active alcoholics (AA) and 8% as inactive alcoholics (IA). Two-day EtOH and BAL were significantly higher for AA than AI and nonalcoholics (NA, and AI higher than NA. Two-day EtOH decreased significantly over time for AA, AI, and NA. These findings indicate that AA among narcotic addicts and those on MMTP consume large quantities of EtOH but that consumption decreases with time on MMTP. The results, in confirmation of the work of others, suggest that entry and participation in MMTP has a broader effect than just on the use of narcotic drugs.