The aim of this study was to describe walking (stride) activity frequency and intensity in 428 children ages 2-15 years with a single accelerometer-based device. With comparison with published pedometer-determined data, the influence of leg length was examined. Decline in stride frequency and intensity throughout childhood increased with adjustment for leg length. The accelerometer-based device documented higher stride counts than published pedometer-based data with the greatest discrepancy in 4-5 year olds. Recommended walking levels for optimal weight throughout childhood should be examined with knowledge of the device measurement differences and the natural history of walking activity changes with age.