We have performed selective posterior rhizotomies on 60 children with cerebral palsy. The procedure involves lumbar laminectomy with stimulation of the rootlets (fascicles) of the second lumbar to the first sacral posterior roots bilaterally; those rootlets associated with an abnormal motor response, as evidenced by sustained or diffused muscular contraction, are divided leaving intact rootlets associated with a brief localized contraction. The patients were between 20 months and 19 years of age representing all degrees of physical handicap and ranging from profoundly retarded to normal intelligence. Follow-up has been from 1 to 5 years. Each child was assessed pre- and postoperatively and graded in the following categories: muscle tone, power, sitting, standing, walking, upper limb function, and speech. The patients whose function improved most dramatically following rhizotomy were purely spastic and intelligent, were significantly more affected by spasticity in the lower than the upper limbs, had some degree of forward locomotion, and could side-sit independently. Patients with severe athetosis or marked contractures improved least.