In order to better understand the transgeneration liability for a substance abuse disorder, we investigated the impact of parental and familial substance abuse disorders on prepubertal boys. Specifically, the influence of each parent's substance abuse history and the effects of significant family aggregation of substance abuse disorders were tested as predictors of the child's behavioral disposition, IQ, and school achievement scores, while controlling for socioeconomic status (SES). Sons of substance abusing fathers were found to have higher externalizing and internalizing problem-behavior scores, lower IQ scores, and lower school achievement scores. Internalizing and externalizing problem-behavior scores were most strongly associated with bilineal parental substance abuse, whereas SES and paternal substance abuse were most strongly associated with IQ and school performance scores. The results are compatible with the hypothesis that although paternal substance abuse has an adverse impact on the son's functioning, bilineal parental substance abuse is associated with the greatest behavioral deviancy among prepubertal males and is associated with a greater liability for substance abuse.