Hypotheses generated by a developmental taxonomy that distinguishes between childhood and adolescent onset conduct disorders were tested. Hypotheses predicted that (1) individual and familial factors would be more strongly related to childhood onset conduct disorder, whereas ethnic minority status and exposure to deviant peers would be more strongly related to adolescent onset conduct disorder and (2) individuals with childhood onset disorder would be more likely to commit violent and victim oriented offenses than individuals with adolescent onset conduct disorder. The first hypothesis was strongly supported and the second hypothesis was partially supported. Implications for early identification of youth at risk for chronic offending are discussed.