The records of 954 ambulatory children presenting for initial evaluation to a university developmental pediatrician were reviewed for the prevalence of persistent toe walking and associated tight heel cords. The incidence of persistent toe walking (20.1%) and tight heel cords (12.0%) were found to be higher in 324 children with an autistic spectrum disorder but lower (10.0%/3.0%) in 30 children with Asperger syndrome. These results confirm the previously reported high incidence of toe walking in children with autism and with language disorders and also raise the possibility of a secondary orthopedic deformity that can complicate long-term management of these patients.