We studied drinking patterns and problems of 451 US Army enlisted men after their return from Vietnam. Before Vietnam, nearly half were regular drinkers and one quarter had drinking problems. Problem drinking declined in Vietnam as opiate use rose sharply; half had tried opiates and 20% were opiate dependent. After Vietnam, opiate use decreased (now less than 2% opiate dependent) and problem drinking again became ascendant. At time of interview, 17% had drunk in an alcoholic pattern at some period in their lives and another 41% had had problems from drinking. The younger men were more likely to have had problems. Alcoholism predictors included: becoming intoxicated at an early age; dropping out of school; truancy and expulsion from school; and having a father with a history of alcoholism or arrests.