In this paper we report on the prediction of mortality, alcohol dependence, and the rate of previously undiagnosed alcoholism in male and female narcotic addicts. These subjects (A' = 200) were initially interviewed upon admission to the Clinical Research Center, National Institute of Mental Health, Lexington, Kentucky, and prospectively followed-up and reinterviewed 5 years later (N= 187). The results indicate that alcoholism and alcohol dependence are very prevalent in this sample of addicts. A history of diagnosable alcoholism obtained at admission was a significant predictor of mortality during the follow-up period whereas a history of heavy drinking was associated with increased mortality but not significantly. About one-half of the males and one-quarter of the females met criteria for alcohol dependence during the follow-up period. Both a prior diagnosis of alcoholism and a history of heavy drinking were significant predictors of episodes of alcohol dependence during the follow-up period. In addition, the proportion of subjects positive for alcoholism increased between two- and threefold during the 5-year period. Finally, a history of heavy drinking at any time within the 4 years immediately prior to admission significantly predicted subsequent episodes during the follow-up period.