Identifying programs that have been proven effective is essential to preventing juvenile violence and delinquency. The Blueprints for Violence Prevention initiative, developed by the Center for the Study and Prevention of Violence at the University of Colorado-Boulder and supported by the Office of Juvenile Justice and Delinquency Prevention, has developed and implemented research-based criteria for evaluating program effectiveness. Given limited resources, communities seek to ensure that the programs they implement will produce the desired results. After reviewing more than 600 programs, the Blueprints initiative has identified 11 model programs and 21 promising programs that prevent violence and drug use and treat youth with problem behaviors. To further assess the effectiveness of the Blueprints programs, OJJDP funded replications of Blueprints programs nationwide- delivering training and technical assistance to 42 sites replicating 8 of the Blueprints model violence prevention programs and to another 105 sites (representing approximately 400 schools) implementing a model drug prevention program. This Report describes the Blueprints programs, presents lessons learned about program implementation, and provides recommendations for program designers, funders, and implementing agencies and organizations. It is hoped that the information provided in this Report will assist communities in selecting and implementing research-based programs that enable youth to fulfill their potential and lead productive lives.