Little is known about the early childhood indicators of adolescent risk. The link between trajectories of externalizing behavioral problems and early adolescent risk behavior was examined in a longitudinal sample of 875 child participants in the LONGSCAN studies. Five trajectory groups of children defined by externalizing behavior problems were identified: Low, Low-Medium, Moderate, Increasing-High, and High. After controlling for demographics and maltreatment, violent/delinquent behavior was significantly predicted by membership in the Moderate and Increasing-High problem behavior groups. Substance use in early adolescence was significantly predicted by membership in the High behavior problem group. These findings suggest that there is a great deal of continuity between patterns of externalizing behavior in childhood and risk-taking in early adolescence. Understanding the course of externalizing behavior in childhood can help identify children at particular risk for more serious behavioral problems in early adolescence. (Contains 3 tables and 1 figure.)