Twenty-five patients with 47 cases of herniated cervical disks underwent CT scans before and after intravenous contrast enhancement and also after intrathecal administration of contrast medium, in order to evaluate the relative efficacy of intravenously enhanced CT among the three method in the detection of corvical HNP findings. Intravenously enhanced CT showed marginal ring enhancement along the posterior margin of the herniated disk and thickened linear blush, and so provided a better delination of HNP findings in 4 cases with focal disk herniation and 3 cases with a far lateral type of disk herniation than did simple CT and myelographic CT. The authors conclude that intravenous contrast enhancement really improves the CT diagnosis of herniated cervical disk, particularly in cases with doubtful focal herniation and far lateral type of disk herniation, and can make preoperative myelography and myelographic CT unnecessary.