The optimal clinical management of aggression in children and adolescents involves both behavioral and pharmacologic intervention strategies. This article reviews medication treatments for youngsters with autistic disorder and conduct disorder, conditions for which the pharmacologic management of aggression is often necessary. Efficacy results and associated adverse effects from selected clinical trials of most classes of psychotropic medications are discussed. While preliminary progress has been made in the development of medication treatments for these serious disorders of youth, additional controlled research and longitudinal studies are needed to better understand the efficacy and tolerability of currently available compounds within each diagnostic group.