Only a limited number of effectiveness studies have been performed to study the benefits of efficacious behavior problems prevention programs for children when implemented through national health service systems. This study uses a quasi-experimental design to test the effectiveness of the school-based PATHS prevention program (Providing Alternative THinking Strategies) when implemented through Dutch municipal health services by health promotion professionals. A sample of 1,294 children was followed for two years: 674 children attending nine schools providing PATHS and 620 children in nine comparison schools. We hypothesized finding an intervention effect of PATHS in terms of a significant reduction in teacher- and student-rated externalizing and internalizing problem behaviors, and a significant improvement in teacher-, student-, and peer-rated social skills and emotional skills. In fact, the results show low levels of program implementation and no intervention effects on problem behavior or social and ... : International Journal of Conflict and Violence (IJCV), Vol 6 No 2 (2012) ...