Purpose: The purpose of this study was to examine physical activity (PA) levels of young children classified by body mass index (BMI) (non-overweight, overweight, and obese) during physical education classes. Method: Participants included 82 children (45 boys, 37 girls; 7.5 ± 1.2 years). PA was determined by the number of steps measured with pedometers. Data were analyzed with a three-way ANOVA (BMI x grade x gender). Results: No interaction was observed. There was a significant main effect for BMI. Children in the non-overweight group took more steps than the children in overweight and obese groups during physical education classes. Discussion/Conclusion: The findings suggest that differences existed in PA during physical education classes in young children dependent on their BMI.