The increasing interest in selective posterior rhizotomy for reduction of spasticity in children with cerebral palsy and other neurological disorders comes from the selectivity that this procedure has achieved with intraoperative electromyographic monitoring. Thirty patients were operated on between April 1989 and October 1991. Spasticity was of cerebral origin in 27 cases and secondary to spinal cord lesion in 3 others. A reduction in the abnormally high muscle tone was observed in all cases, mainly in the lower extremities, but also, to a lesser degree, in the upper extremities. All patients showed functional improvements that depended on the individual preoperative condition. Even severely disabled patients with quadriplegia and intellectual impairment, whose spasticity interfered with their daily care, had a significantly improved quality of life after rhizotomy. These patients became much looser, with better swallowing and less drooling, and were much more easily managed by their caretakers. Preliminary results with follow-up from 1 to 30 months indicates that selective posterior rhizotomy is a safe procedure which contributes to significant functional improvement in spastic patients.