Serial casting to stretch the plantar-flexors has been advocated for idiopathic toe-walkers (ITW) and children with spastic cerebral palsy (CP), although outcomes have not been well studied. Neuromuscular function and gait were examined in eight children with CP (mean age, 7.1 years) and eight ITW (mean age, 7.5 years) casted for 3 to 6 weeks. Baseline comparisons indicated that children with CP produced lower isometric plantar-flexor torques (p< 0.02) concomitant with marked co-contraction (p< 0.001). greater ankle mobility (p< 0.02), and higher reflex excitability (p< 0.001) than ITW. After casting, both groups increased dorsiflexion range (p< 0.001), decreased resistance to passive stretch (p< 0.005), and produced maximal plantar-flexor torques in dorsiflexed positions (p< 0.001). Reflex excitability was reduced in CP (p< 0.05). Immediately postcasting, no children toe-walked, but two with CP resumed a digitigrade pattern 6 weeks later. Gait velocity and stride length did not change (p>0.05). Serial casting yielded positive outcomes that may be longer lasting in ITW.