The purpose of this study was to examine age-related physical activity patterns in youth with autism spectrum disorders (ASD). Thirty youth, aged 10-19 years, were divided into three groups: elementary (n=9), middle (n=9) and high (n=12) school. Participants wore an accelerometer and completed an activity questionnaire for seven consecutive days. The main findings were that (a) elementary youth are more active than the other groups, regardless type of day or time period, and (b) there are no consistent patterns in physical activity of youth with ASD according to day or time period. Findings emphasize that interventions for this population should address increasing extracurricular physical activity options during adolescence.