Among the patients operated because of lumbar disc herniation from Jan. 1973 to May 1979 at Korea University Hospital, 154 cases were analyzed radiologically and the following conclusions were obtained. 1. The ratio of maleto female was 1.96:1. 2. The incidences of single and multiple involvements were 74.7% and 25.3%. 3. Most frequent level of lumbar disc herniation was L 4-5 interspace. 4. The incidences of left, right, central and bilateral defects were 45.45%, 33.76%, 12.33% and 8.44% respectively. 5. The incidences of spina bifida and transitional vertebral were 24.04% and 9.09% respectively. 6. The overall mean of the lumbosacral angle was 33.97degrees. 7. The overall mean depth of the lumbar lordosis was 8.48mm. 8. The ratio of the height of L4-5 interspace to the shortest anteroposterior diameter of L-5 body was obtained by Author's idea. The mean ratios of male and female patients of L4-5 disc herniation which had no evidence of the narrowing of L4-5 interspace on simple radiologic finding were 0.3042 and 0.3064 respectively, and the mean ratios of male and female in normal group were 0.3347and 0.3493 respectively. So the ratio had a little value in the diagnosis of L4-5 disc herniation on simpleradiologic study. 9. Myelography had high diagnostic accuracy, and the majority of the pseudo negative finding onlumbar disc herniation myelographically was seen at L5-S1 disc herniation.