The prevalence and rise of obesity among children is alarming. Over the past thirty years, the percentage of obese children aged 6 to 11 has tripled. Concurrently, the number of obese preschool children and adolescents has doubled. It is well documented that proper nutrition and regular physical activity are key factors in reducing childhood obesity. Current efforts to increase physical activity and reduce childhood obesity focus on the built environment, of which public playgrounds play an integral role. For adults, the prevalence of obesity and overweight is problematic as well. More studies are needed that focus on physical activity in or related to playgrounds. This is an important gap in the active living research literature. The purpose of this study was to measure (1) Leisure Time Physical Activity (LTPA) levels (i.e., sedentary, moderate, and vigorous) in playgrounds in selected neighborhood parks using direct observations, and (2) the association between physical activity levels, age, and gender. Data were obtained from 11 public neighborhood parks in Tampa FL, and 18 neighborhood parks in Chicago, IL. Trained observers recorded LTPA between 10AM and 6PM from Friday through Sunday using the System for Observing Play and Leisure Among Youth (SOPLAY) (McKenzie, 2002). Primary activity observation codes accounted for age (youth/adult), gender, and activity levels (sedentary, moderate, and vigorous). A total of 9,409 park users were observed, with 6,996 in Tampa and 2,413 in Chicago. Across both cities, 19.8% of park playground users (adults and children) were categorized as vigorously active, 26.5% were moderately active, and 53.7% were sedentary. For Tampa, 17.5% of park playground users (adults and children) were vigorously active, 27.1% were moderately active, and 55.3% were sedentary. Among children, 26% were vigorously active, 28.4% were moderately active, and 45.6 % were sedentary. For Chicago, 26.3% of park playground users were vigorously active, 24.6% were moderately active, and 49.1% were sedentary. Among children, 32.2% were vigorously active, 25.4% were moderately active, and 42.4 % were sedentary. In both Tampa and Chicago, female children were more active than male children. Future studies should further investigate the associations between LTPA and the built environment, in order to encourage and increase physical activity on playgrounds. Such research is needed to inform design and management of parks, and playgrounds within parks, to support active living. This study was supported by a grant from the Robert Wood Johnson Foundation, Active Living Research Program.Keyword(s): exercise/fitness/physical activity, health promotion, recreation