The preschool years are a critically important period for developing healthy food preferences and motor skills. Since the majority of U.S. children are placed in some form of non-parental care during their preschool years, these settings provide opportunities to promote healthy eating and physical activity behaviors among preschool children. Given the widespread use of child care, an understanding of current practices relevant to nutrition and physical activity in child-care settings is needed to inform obesity prevention efforts. Prepared jointly by RWJF’s Healthy Eating Research and Active Living Research programs, this research synthesis reviews studies that have identified opportunities to promote a healthy diet and regular physical activity among preschool children. It also examines outcomes of research interventions designed to prevent obesity in child-care settings.