Decades of research in juvenile and criminal justice, developmental psychology, epidemiology, and other disciplines, including evaluations of promising program interventions, should inform policymaking, decisionmaking, and the development of programs and treatments. Working as a multidisciplinary team, juvenile justice and child welfare system practitioners, researchers, and experts in the community should combine their clinical experience with this growing body of knowledge. For decades, juvenile justice researchers and social scientists have been studying the causes and correlates of delinquent behavior and identifying a variety of risk factors for delinquent behavior that could assist the court in designing and adopting earlier and more effective interventions. Sound intervention by the juvenile court requires specific inquiry into a particular child's family, school performance, social activities, and other circumstances to identify risk and protective factors present in the child's life. Prevention efforts should include intensive, individualized intervention in the lives of dependent children so that the dichotomy between interventions with delinquent and dependent youth and between the way their cases are handled can be dissolved. The response of the juvenile system must be collaborative and interdisciplinary. This requires that interdisciplinary training be provided to court staff, judges in particular. A fully functioning professional juvenile court has the potential to be the most effective prevention tool in the juvenile justice system. 5 notes and 22 references