This session of Grand Rounds will explore the societal burden of youth violence, and the evidence-based approaches and partnerships that are necessary to prevent youth violence and its consequences. Homicide, the third leading cause of death among young people 10 to 24, is responsible for more deaths in this group than the next six leading causes of death combined. Each day, there are 13 homicides in this age group and an additional 1,700 youth treated in U.S. emergency departments for assault-related injuries, resulting in an estimated $17.5 billion in total costs per year. While many prevention programs have been found to significantly reduce youth violence, the available evidence-based approaches are often not used in communities because of real and perceived challenges to implementation. Some communities and public health departments have successfully built the capacity to take advantage of what we know works and are seeing substantial declines in youth violence.