This study evaluates the effects of an indicated preventive intervention and a universal preventive intervention. Children were identified as being at risk on the basis of 4th-grade teachers' ratings of children's aggressive and disruptive behaviors, and interventions were delivered during the 5th- and 6th-grade years. Children were randomly assigned to the Coping Power intervention, the universal intervention, the combined Coping Power plus universal intervention, or a control condition. The Coping Power program included child and parent components. Results indicated that all 3 intervention cells produced relatively lower rates of substance use at postintervention than did the control cell. The interventions also produced effects on 3 of the 4 predictor variable domains: children's social competence and self-regulation and parents' parenting skills.