The purpose of this review is to discuss issues in the prevention of serious conduct problems among children and adolescents with attention deficit/hyperactivity disorder (ADHD). The authors began by reviewing research on the common genetic and environmental etiological factors, developmental trajectories, characteristics and impairments associated with ADHD and comorbid oppositional defiant and conduct disorders. Next, the authors presented empirically based models for intervention with children and adolescents with ADHD that are at risk of developing serious conduct problems and detailed the evidence supporting these models. Researchers have demonstrated the utility of medication and psychosocial intervention approaches to treat youth with these problems, but current evidence appears to support the superiority of multimodal treatments that include both approaches. Future directions for researchers are discussed.