Organized afterschool programs have received increased attention over the past two decades because of changes in family demographics and in society's structures for supervising and socializing youth. The number of afterschool programs has been rapidly expanding to meet the increased need. However, not all youth in need are being reached, and the programs that are being created are loosely connected. The authors present several advantages of more fully integrating sport and afterschool activities. There are well-documented positive effects of physical activity and sports participation on physical and psychosocial youth outcomes, especially if those programs are implemented with these points in mind. Promoting healthy lifestyles and preventing obesity are also important federal- and state-level policy priorities. Finally, physical activity and fitness and sport participation are linked with improved cognitive functioning and greater academic achievement, two desired outcomes of many afterschool programs. The authors note, however, that many youth sports programs designed to enhance positive youth development will not succeed without more attention focused on improving them, because they do not use best practices and principles of afterschool and youth sports programs. The authors focus on best practice ideas in four areas that are essential to the successful intersection of youth sport and afterschool programming: setting a clear mission, programming with appropriate content, staff training, and research and evaluation or frequent assessments. They illustrate best practices in each of these areas using program descriptions and provide recommendations for strengthening the connections among afterschool programs, sports, and physical activity. (Contains 52 notes.)