This study examined whether organized sports participation during childhood and adolescence was related to participation in sports and physical fitness activities in young adulthood. The data were from the Michigan Study of Adolescent Life Transitions. The analyses include more than 600 respondents from three waves of data (age 12, age 17, and age 25). Childhood and adolescent sports participation was found to be a significant predictor of young adults' participation in sports and physical fitness activities.