The sample was composed of 204 HIV-positive and HIV-negative drug-using fathers and their adolescent children. Each pair of fathers and adolescents was administered individual structured interviews by trained interviewers. The interview consisted of a number of widely used scales that assessed father and adolescent personality characteristics, father drug and/or alcohol use and HIV status, the father-child relationship, peer influences, and environmental factors. The dependent variable, frequency of adolescent alcohol use, was a composite index derived from a question about the frequency of the adolescent's use of beer and wine during the past year, as well as the frequency of the adolescent's use of hard liquor during the past year. This study tested a mediational model that examined the mechanisms that link father's attributes to adolescent alcohol use. Regarding specific aspects of the mediational model, the study findings indicate that the youth's personality was the mediator between most of the other domains, i.e., father attributes, father-child relations, and environmental factors, and the dependent variable of adolescent alcohol use. The adolescent's deviance-prone personality profile was related to the adolescent's drinking, and the effect of the father's child-rearing practices on the adolescent's alcohol use was mediated by the youth's personality. The peer group had a direct effect on adolescent alcohol use, as adolescents whose friends used alcohol, marijuana, and/or other drugs were themselves more likely to engage in these behaviors. The perceived environmental influences on adolescent drinking were mediated by the adolescent personality. Particularly important is the finding that children who drink with their fathers are more likely to become heavier drinkers in adolescence. Given the prevalence of alcohol use among youth whose fathers are substance abusers, prevention and treatment should be implemented with fathers and their children to reduce the negative effects of paternal risk factors and to increase the effectiveness of paternal protective factors. 3 tables, 3 figures, and 77 references