This update presents current empirical knowledge on the development of serious and violent criminal behavior by juveniles, associated risk factors, and the most effective interventions for preventing and reducing such juvenile crime. A second objective is to place Dutch findings on this topic in an international context. The first section focuses on trends in serious, violent, and persistent juvenile delinquency between 1950 and 2004, along with some key features of the link between serious, violent, and persistent forms of delinquency. Section II addresses the study of juvenile sex offenders and sexual violence as a specific form of violent juvenile delinquency. A review of recent findings considers the prevalence of juvenile sexual offenses, male group rapists, child molesters and peer abusers, juvenile offenders who commit only sex offenses and those who commit both sexual and nonsexual offenses, female sex offenders, reoffending, and care and treatment. Section III discusses the link between ethnicity and juvenile delinquency. Although the prevalence of violent crime is higher among Moroccan youths, and the prevalence of drug-related crime is higher among Antillean youths than among other ethnic groups and native youth, it remains unclear why these patterns have emerged. The remaining sections update findings on the co-occurrence of serious and violent delinquency with other behavioral problems, the prevalence and development of antisocial behavior, family factors, the screening of serious and violent juvenile offenders, prevention, interventions, police and justice interventions, and next steps. 3 tables and 150 references