We examined the rates of postoperative neurologic complications, as recorded in the medical record department in Severance Hospital from 1989 through 1991 for patients who had had operations on the spine. There were 538 hospitalizations for procedures on the spine; 327(60.78%) of herniated disc, 120(22.30%) of spondylolisthesis, 64(11.90%) of infection, 27(5.02%) of spinal stenosis were included. Neurologic complications oecurred in 12(2.23%) patients; 3 cases in herniated disc, 4 in spinal stenosis, 4 in spondylolisthesis, and 1 in infection. Regarding techniques of the operation, 8 complications occurred in arthrodesis, among these, 2 were in anterior approach and 6 in posterior approach. Four cases of the complications occurred in laminectomy and discectomy procedure. Complications were more frequent in the patients who had had spinal stenosis when arthrodesis was performed than decompression procedure only. Possible causes of neurologic complication were postoperative hematoma formation, translation of the vertebral column due to instability after anterior debridement and forceful traction of the nerve root during the operation.