The herniated nucleus pulposus(HNP) is a major cause of low back pain and sciatica. High resolution CT is themost accurate diagnostic tool to define a HNP, because it provides a complete in vivo analysis of bony frameworkof lumbar spine as well as the supporting soft tissue structures and neural elements. But the discrepancy betweenneurologic findings and CT findings is often confusing. From May 1983 to August 1986, sixty patients with HNP whohad both CT & surgical intervention at Pusan National University Hospital were analized. The fallibility of theneurologic examination on HNP and the effect on HNP on nerve root were evaluated on the basis of CT findins. Theresults were as follows: 1. Thirty-four cases(56.7%) of clinical impressions were matched to CT findings indeterming level of HNP and affected nerve root. 2. In evaluation of affected level, there was high trend to causediscrepancy between neurologic findings and CT findings in multiple disc involvment than in single involvement. 3.There was no correlation between degree of nerve root compression determined by CT and pattern of neurologicsigns(motor weakness, sensory deficit, and reflex change).