Selective posterior rhizotomy (SPR) is a neurosurgical procedure designed to alleviate spasticity and has been successfully used for children with spastic cerebral palsy. In our hospital, 30 patients had undergone SPR between June, 1988 and June, 1992, and the only 20 patients were followed over 6 months after operation. The authors have analyzed the status of 20 children with spastic cerebral palsy before and after operation to determine the effects of this therapy on muscle tone, range of movement and motor function. Postoperative tests showed a reduction in muscle tone in all cases compared with preoperative assessments. Range of motion in lower extrimities was increased in 65 to 85% of cases while motor function continued to improve in 10 cases. Functional gains were greatest in children operated on under the age of 5. The complications of SPR were not serious only one case had transitory bladder problem, 2 cases had mild spinal instability, 2 cases had mild scoliosis.