Funded by First 5 LA, Los Angeles Universal Preschool (LAUP) is a nonprofit organization whose mission is to provide access to high quality preschool education for the children of Los Angeles County. Both First 5 LA and LAUP sponsor activities aimed at promoting children's physical health. To inform these efforts, First 5 LA contracted with Mathematica Policy Research to examine how LAUP center-based and family child care (FCC) programs promote physical activity among children. This work was conducted as part of the Universal Preschool Child Outcomes Study (UPCOS). Table 1 presents the UPCOS data sources and study sample. This issue brief highlights key findings about rates of obesity and overweight, time spent in physical activity, gender differences in play activities, and teachers' approaches to encouraging activities. Additional study findings on these and related topics are covered in Aikens et al. (2013). (author abstract)