Studies on adult sex and violent offenders have found high rates of adolescent delinquency, while early delinquency has been shown to be significantly associated with adult offending. The examined sample represents a sub-sample of an age cohort of a longitudinal prospective study (N=6315) including all men who at the age of 19 had an entry in the criminal records (N=123). During the observation period of 34 years, 68.3% of the sample had been reconvicted as adults, 23.6% for violent or sex offenses. Of the adolescent delinquents who went on to adult violent offending the odds for adult sex or violent offending were 2.8 times elevated for those who had committed a violent offense in adolescence and 2.5 times elevated per type of offense committed in adolescence. Additionally, each offense committed before the age of 19 lead to a 5% increase in risk for violent or sex offending as an adult. The characteristics of criminal history showed the highest discriminative values (AUC: 0.61-0.65). The most important finding of this study was that characteristics of adolescent delinquency such as versatility, violence and frequency are better predictors of adult violent offending than socio-economic or psychiatric ones.