Background:No prior studies have assessed the relationship of school-sites with children's fitness, nor evaluated how it is influenced by types of built environments surrounding school-sites. Purpose: To create a typology of school-sites and assess their associations, with school-level cardiorespiratory fitness (PACER score), as well as 34 environmental measures, reflecting food retailers and parks. Methods: PACER scores (#laps) were obtained on 20,900 children, 5-18 years-old, attending 103 rural and urban public schools in Wisconsin 2009-2010. Scores were aggregated at the school-level (mean 25.2±10.5). School-site typology reflects walkability context and parcel size. Schools were classified as: Neighborhood-School, Neighborhood-Campus, Neighborhood-Suburban, or Campus-School. Geospatial and linear regression were performed , overall and by sex and age strata, using a 1600-meter circular buffer around each school. Associations with school-level-PACER score were assessed for school types; density of unhealthy and healthier food retailers; and types of parks. Results: Campus-Schools predict a school average-PACER 7 laps significantly higher than Neighborhood-schools. 'Neighborhood-Campus' showed the lowest PACER for males and 11-13 years-old (10 and 12 laps lower). Negatively correlated with average-PACER were, unhealthy convenience stores for both sex, large parks for females. More fast-casual restaurants predict higher average-PACER. Schools with more students predict higher average-PACER for males and 6-10 years-old. Conclusion: Among Wisconsin schools, school-site and its context are associated with children's physical fitness, suggesting that school-siting should include a health benefit analyses in the process. This study demonstrates the utility of school-level PACER scores and suggests further study of the mechanisms by which children's fitness is influenced by food retailers around school zones. ABSTRACT IRJPH: https://escipub.com/international-research-journal-of-public-health/ 1Milena Bernardinello and Aaron L. Carrel, IRJPH, 2019; 3:31 IRJPH: https://escipub.com/international-research-journal-of-public-health/ 2 7 U.S. Census SAIPE 2010 -https://www.census.gov/programssurveys/saipe/data/datasets.2010.html 8 UW-Madison GeoData portalhttp://maps.sco.wisc.edu/opengeoportal, 2018 9 UW-Madison State Cartographer's Officehttps://www.sco.wisc.edu/data/parcels/