The lack of quality physical education, as well as the absence of health and wellness concepts being taught, (particularly in California) results in children graduating from elementary school with poor levels of physical activity and fitness. Project Health Zone (PHZ), a pilot program designed to assist in the delivery of physical education to K-2 students, includes a physical education program focusing on health and wellness components through physical activity. PHZ's goals are to increase moderate and vigorous activity during recess thus increasing children's daily physical activity. Recess can provide additional time children spend in moderate and vigorous activity. The purpose of this study was to investigate the effects of a comprehensive quality physical education curriculum on physical activity during in-school recess. Each child's physical activity was assessed using SOFIT measures of physical activity. One hundred and seven 4-8 year old elementary students were observed during three pre (September) and post sessions (April). Fifty intervention students from the PHZ physical education classes and 47 students from the control group, received physical education from their classroom teachers, were observed during recess using the System for Observing Fitness Instruction Time (SOFIT). Activity categories were analyzed using Repeated Measures ANOVA. Intervention students significantly increased their time being very active and decreased their time sitting and standing. A significant change pre to post in frequency of walking and being very active was also noted. The control students' results indicated little change and individual results suggested less activity. More sedentary activity (sitting, standing) by the control group as well as a higher incidence of consumption of food prior to engaging in free-play/exercise was also found. Control students were observed in larger cliques, and participating in activities that reduced moving due to structure (12-15 students playing half court basketball). Intervention students were organized in smaller groups thus promoting more individual interaction within the activity therefore increasing physical activity. These findings help support the need to include quality activity based physical education programs as part of the solution to increasing activity levels outside of the classroom. Current unstructured physical education classes do not adequately develop skill in fundamental movement patterns, and do not provide opportunities to learn about the importance of daily physical activity that could transfer to recess. This study contributes to the literature supporting quality physical education taught by trained professionals in elementary schools. Keyword(s): active participation, elementary issues, physical education PK-12