Seasonal variation of American Indian children’s school-day physical activity Study aim: To examine the pedometer steps taken during the school-day by American Indian children during all four seasons. Material and methods: Participants included third-sixth grade children (n = 157) aged 9.6±1.07 (boys) and 9.7±1.2 (girls) attending school from one Southwestern US American Indian community. Children had a mean BMI of 23.9±7.7 with 70% being classified as overweight or obese. Children wore a pedometer (Yamax Digiwalker SW-200) for 20 days (5 days per season). Results: Children accumulated 4762±1544 (boys) and 4408±1194 (girls) steps/day across the four seasons with the highest totals occurring during the Fall (4899, males; 4796, females) and the lowest totals during the Winter (4463, males; 4043, females). Repeated measures ANOVA showed no significant differences in daily school-day steps across seasons. Children classified as normal weight averaged 5146±1688 steps/day, overweight children averaged 5020±1333 steps/day, and obese children accumulated 4275±1123 steps/day. Conclusions: PA stayed relatively consistent across seasons in this sample of children. However, children were the least active during Winter months. With 70% of the current sample being classified as overweight and with American Indian children at greater risk for numerous hypokinetic diseases there is a clear need for additional school-day PA opportunities.