Facilitation and recovery of the H-reflex were studied in 63 children with cerebral palsy, and the results were compared with those obtained for 60 normal children. H waves were recorded from the gastrocnemius with surface electrodes, after applying paired stimulations to the tibial nerve in the midpopliteal crease. In normal children, both the facilitation and the recovery showed a tendency to decrease with their development, while those for children with cerebral palsy were more marked than normal children in all age groups. The present study indicated that the excitability of spinal alpha motoneurons and the subliminal fringe in the motoneuron pool might change due to the maturation of and the damage to the central nervous system in children. We consider that H-reflex examination provides useful information for the supraspinal control to the spinal mechanism to regulate muscle contraction in children as well as in adults.