Purpose: Pediatric physical therapists are becoming increasingly involved in designing and implementing fitness programs for both typically developing children and children with cerebral palsy. This review discusses some of the methodological challenges associated with evaluating aerobic exercise in children, as well as current evidence on the effects of aerobic exercise for children with motor disabilities, specifically cerebral palsy. We then provide some general guidelines about implementing aerobic exercise programs with children. Summary of Key Points: Our knowledge of the effect of aerobic fitness programs in children is limited. Research designs that fail to control for important child variables such as age and maturity; inadequate control of program parameters such as intensity, duration, and frequency; and the use of many different outcome measures make it difficult to discern the true effects of aerobic exercise. Furthermore, outcomes evaluating the components of activity and participation are seldom included. Conclusions: Recent research suggests that children, both typically developing and those with chronic conditions, can benefit physiologically from aerobic exercise. However, the effect of aerobic exercise on functional outcomes for children with motor disabilities is not well understood.