Introduction Physical inactivity and childhood obesity are prevalent in American children, with increased vulnerability in minority, low-resource populations. The aim of this study was to quantify the impact of physical education (PE) on in-school physical activity quantity and intensity in urban minority children attending public elementary schools. Methods This observational study included elementary children (N=212; mean age, 9.9 years; 81.7% black) in Grades 2-5 attending urban public schools with high eligibility for the National School Lunch Program. In-school physical activity was quantified during 4 school weeks across 4 months (January-April 2012) using Omron HJ-151 accelerometer-pedometers. Fitness was assessed with the 20-meter Progressive Aerobic Cardiovascular Endurance Run. Data were analyzed in 2013 using generalized estimating equations to determine the influence of PE and sex on total in-school steps and moderate to vigorous physical activity (MVPA) steps. Results Based on 3,379 observation days (mean, 15.9 school days/student), students achieved higher in-school physical activity on days with PE (4,979 steps) than on days without PE (3,683 steps, p<0.0001). Likewise, MVPA steps were greater on days with PE than on days without PE (p<0.0001). Boys were more active than girls, but both accumulated more steps on days with PE. Low aerobic fitness was observed in 29.0% of students and overweight/obesity in 31.1%. Conclusions PE significantly increases total in-school and MVPA steps in urban minority elementary children. PE as a core subject can provide opportunities for urban, minority public school children in low-resource areas to achieve age-appropriate physical activity and fitness goals.