Out of 22 evaluations, the experimental group did better than the control group of 19 cases, and the differences were significant. The median decrease in reoffending in the experimental group compared with the control group was 35 percent, which seems a substantial effect. It is concluded that the best evaluations generally show that family-based programs are effective in reducing later offending. Based on a previous review of 40 evaluations, this paper sought to present a more systematic review on the effectiveness of family-based prevention programs in reducing delinquency and later offending by children and adolescents. The results so far are very promising. Future research is suggested for a large-scale evidence-based national program to evaluate the effectiveness of family-based interventions. Tables, references