PURPOSE: To explore the feasibility and efficacy of stepping while standing and its effect on function and prevalence of secondary conditions among children with severe cerebral palsy. METHODS: Of 22 children with severe cerebral palsy, 11 underwent treatment using a Hart Walker (HW) device, and the other 11 underwent a passive standing program. Constipation prevalence and adverse events were recorded. Bone quantitative ultrasound was performed for the tibia. The Pediatric Evaluation of Disability Inventory was used to assess activities of daily life. RESULTS: Children exposed to the HW improved bowel function, but no added quantitative benefit to bone was observed when compared with passive standing. Children using the HW were able to take steps independently in the device, but did not reach a functional walking level. CONCLUSIONS: Providing a child who is nonambulatory the opportunity to walk may be important both for participation in activities of daily living and social roles and for preventing secondary conditions.