The search for ways to prevent juvenile crime in the United States has become a matter of national urgency, as the incidence of serious offenses continues to rise. Most prevention initiatives focus on late childhood or adolescence. Such initiatives may be missing an important additional opportunity to intervene earlier in children's lives. This review of literature from criminology, psychology, and education shows that there exist key early childhood factors which are associated with later antisocial or delinquent behavior and that early childhood programs which seek to ameliorate the effects of those factors can prevent later antisocial or delinquent behavior. In particular, the review focuses on programs which have demonstrated long-term effects on antisocial behavior or delinquency. These programs have in common a combination of intensive family support and early education services, and effects on a broad range of child and family risk factors for delinquency. Moreover, there is promising evidence of their cost-effectiveness. As one element in a comprehensive plan to address poverty and other environmental causes of crime, programs combining family support with early education show promise in lessening the current devastating impact of delinquency on America's children and families.