A series of 84 cases operated upon for herniated intervertebral disc of lumbar region was studied with respect to the diagnostic value of myelographic examination. Various clinical signs including level of tenderness, sensory impairment, motor weakness, door-bell sign and Lasegue test, were reviewed. The clinical diagnosis derived from these signs was correct in 54.8%. The plain X-ray film showed narrowing of disc space in 44 cases. As to the myelographic findings, mode and level of indentation, positive and negative findings were analyzed and comparisons were made with operative findings. Among 84 cases, 47 cases showed lateral indentation, 32 cases central and 5 cases complete block. As to the level, L4~5 disc space was dominant. As a whole, the myelographic findings accurately corresponded with the operative findings in 77.4%, 65 cases. However, diagnostic accuracy was varied according to level, i.e., in case of L4~5 disc herniation, 45 cases among 53 cases showed correct myelographic diagnosis, while only 10 cases among 17 cases showed correct myelographic diagnosis in L5~S1 disc herniation. In addition, if electomyography and discography are added as diagnostic aid, the preoperative diagnostic accuracy will be higher but those are not available in our circumstance.