Neurofibromat osis is a familial discase with widespread manifestations such as lesions of the skin, tumors of the central and peripheral nervous system and abnormalities of bone. The presence of at least two of the following features was considered for diagnostic criteria; positive family history, positive blopsy, a minimum of six cafe-au-lait spots each with a diameter of at least 1.5 cm and multiple subcutaneous nodules. From January 1971 to December 1979, 17 patients of neurofibromatosis and 30 patients of neuro- fibroma treated at Yonsei Medical Center were clinically analized for the study and the results obtained from this study were as follows; 1. Positive family history was obtained In 2 per cent of cases with neurofibromatosis. 2. Cafe-au-lait spots or tumors were the most common findings in neurofibromatosis. The bone changes were presented in 8 patients(45 per cent) and scoliosis has been In 62.5 per cent of them. 3. The location of the neurofibroma was variable. Central nervous sustem was involved in 40.4 per cent and peripheral nervous system in 59.4 per cent. 4. Myelography and determinations of the cerebro-spinal fluid protein concentration led us to a correct diagnosis of the neurofibroma which involved the spinal cord. For the treatment of the neurofibroma, 9 out of 30 patients were performed laminectomies and excision of the intradural masses, and one of them was flxed the spinous processes with a plate and wires after laminectomy for prevent spinal instability. 5. in 3 patients with progressive scoliosis, the best results were obtained with early Harrington instrumentation and posterior fusion.