The concurrence of substance abuse and history of sexual abuse among adolescents has prompted this study of substance abuse patterns among families of adolescents who report incest or extrafamilial sexual abuse. A total of 3,179 ninth-grade students in a rural midwestern state completed a survey that included questions about individual and family substance abuse. Adolescents who had been sexually abused were more likely to report substance abuse for themselves as well as for members of their immediate families. They were also more likely to report that they used substances because of family problems, school problems, and because they were sad, lonely, or angry. Adolescents reporting a parent with an alcohol or a drug problem were more likely to use cigarettes, marijuana, alcohol, or "speed." Adolescents experiencing extrafamilial abuse reported more alcohol abuse and more alcohol-related problems than those who experienced incest. There were similar reports of parental and familial alcohol and drug problems among these experiencing incest and those experiencing extrafamilial abuse. Those with drug-abusing parents, however, were most likely to report some kind of sexual abuse history.