Child-care settings provide numerous opportunities to promote healthy eating and physical activity behaviors among preschool children. The majority of U.S. children are placed in some form of non-parental care during their preschool years. While approximately 15 percent of preschool children are primarily cared for by their relatives, most preschoolers who spend time in non-parental care arrangements are placed in center-based care (e.g., child-care centers, preschools, Head Start programs) or a family child-care home. 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. 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. (Contains 1 figures, 4 tables, and 76 footnotes.)