We investigated the independent contributions of maternal history of antisocial behavior and parenting practices to the worsening course of sons' behavior problems in a sample of young urban boys at risk for antisocial behavior. Mothers reported on boys' behavior problems at baseline and one year later, as well as on their own history of antisocial behavior before and after age 15, and of lifetime depression and substance use disorders (provisional DSM-III-R diagnoses). Baseline reports of parenting practices were obtained. Lower involvement, lower monitoring, and higher levels of parent-child conflict and maternal Conduct Disorder (CD) before age 15 contributed to the worsening of boys' behavior problems one year later; mothers' symptoms of Antisocial Personality Disorder after age 15 did not. Mothers' lifetime history of Major Depression and Substance Use Disorder did not add to the worsening of boys' behavior problems after accounting for these other factors. Although maternal CD contributed directly to the worsening of boys' behavior problems, the effect of parenting was more substantial. We discuss clinical implications for prevention and treatment of children's antisocial behavior, and intergenerational implications of girls' early antisocial behavior.