The herniated nucleus pulposus is a major cause of low back pain and sciatica. High resolution compute tomography is the most accurate diagnostic tool to define a HNP, because it provides a complete in vivo analysis of bony framework of lumbar spine as well as the supporting soft tissue structures and neural elements. But the discrepancy between neurologic findigs and CT findigs is often cofusing. From May 1983 to August 1986, sixty patients with HNP 재 had both CT & surgical intervention at Pusan National Univ. Hospital were analized. The fallibility of the neurologic examination on HNP and the effect of HNP on nerve root were evaluated on the basis of CT findings. RESULT : 1. Thirty-four cases of clinical impressions were matched to CT findings in deterning level of HNP and affected nerve root. 2. In evaluation of afected level, there was high trend to cause discrepancy between neurologic findings and CT findingsin multiple disc involvement than in single involvement than in single involvement. 3. There was no correlation between degree of nerve root compression determined by CT and pattern of neurologic signs.