In the great majority of cases with backache, a herniated disc is by far the commonest cause. A high degree of accuracy of diagnosis may be achieved by detailed history, careful examination, and X-ray findings(plain radiography and myelography). The plain radiography and myelography (pantopaque) were conducted on surgically verified 110 Korean patients who were treated at NPH from June 1973 to May 1978. The purpose of this investigation is to establish the roentgen signs of lumbar disc herniation and mainly to analyse the radiological findings and operative findings of 110 cases. The results were as follows: 1. Male to female sex ratio was 8 : 1. Incidence was most eommon in 3rd decade as 41.8%. 2. In plain radiography, about 40% showed signs, and 15.4% of the 110 cases revealed no specific abnormality. The most important positive signs were a relative narrowing of intervertebral disc space (54.5%), straightening of lumbar curve (38.2%), spurring (27.3%) and scoliosis (3.6%). . 103 cases of 110 surgically confirmed disc herniation(93.6%) had single involvement, and 7 cases(6.4%) involved double levels. 4. Among the 110 confirmed cases, myelographic findings were consisted of the unilateral defect : 79 cases(71.9%), central defect : 9 cases (8.2%), bilateral defect : 12 cases (10.9%), and false negative findings : 3 cases (2.7%). 5. 76 cases of 110 operatively verified disc herniation were located at L4-L5 space, and 19 cases (17.3%) were located at L5-SI space. Rt to Lt ratio was 1 : 1. 6. 8 cases (7.2%) showed discrepancies between myelographic and operative findings. Diagnostic accuracy of myelography was 92.8%.