Failure to tolerate medical practices and healthcare routines can deter pediatric patients with neurodevelopmental disabilities from receiving required services. This case study evaluated behavioral intervention to establish tolerance of casting procedures in a 10-year-old boy with autism spectrum disorder (ASD) so that custom ankle-foot orthotics could be prepared as treatment for his idiopathic toe walking. At baseline, casting could not be completed because the boy displayed unsafe resistant behavior. An intervention plan combining graduated exposure, positive reinforcement, and non-contingent access to preferred objects allowed the boy to tolerate a simulated casting protocol and actual casting performed by an orthotist. Service practitioners who implemented intervention rated the plan positively.