The first myelography with air was carried out by Walter Dandy in 1919, and the myelography with positive contrast medium was done by Sicard and Forestier in 1922. Since Pantopaque was adopted as a contrast material by University of Rochester group in 1944, it has been rapidly popularized. Although higher diagnostic accuracy has been made with a development of the diagnostic aids such as electromyography, discography, epidural venography and computerized tomography, myelography has been popularized in our country with electromyography. The authars have seen and studied 107 cases of herniated lumbar disc with respect to the diagnostic accuracy of myelographic examination from January, 1976 to December, 1981 at the department of Orthopedic Surgery, Yonsei University College of Medicine. The results were as follows: l. Of the 107 cases, 59 were found in the age of 20 to 40 years and the ratio of male and female was 2:l. 2. Fifty eight cases (54.2%) had no history of back injury, but 40 cases (37.4%) had sprain of the back and 9 cases had direct trauma history. 3. In all cases, plain X-ray and myelogram were taken. Among them 55 cases showed narrowing of intervertebral space in plain film, and 100 cases showed positive myelographic findings such as lateral indentation of dural sac (41 cases), hour-glass defect (30 cases), root sleeve defect (12 cases), block defect (10 cases) and combined defects (7 cases). 4. Sixty one cases which confirmed by operation, the most frequent level of disc herniation was in L4-5 space. Clinical diagnosis was correct in 57.4%, and myelographic accuracy was coincided with operative finding in 80.3%. 5. Twelve (19.7%) of the 61 cases showed discrepancy between myelographic and operative findings, and these 12 cases consisted of 5 cases of level discrepancy, 3 cases of false positive and 4 cases of false negative.