Three dogs referred to Veterinary Medical Teaching Hospital, Seoul National University were diagnosed as intervertebral disc disease. Physical examination, neurologic examination, survey radiograph, and myelography were performed in patients. Case 1 showed narrowing intervertebral space and calcified intervertebral disc material in survey radiograph. Case 2 showed increased opacity in the intervertebral opacity in survey radiograph. All of 3 cases showed extradural pattern during myelography. In survey radiography, radiographic signs consistent with intervertebral disc herniations include narrowing of the disc space and the dorsal intervertebral articular process joint space, small intervertebral foramen, increase opacity in the intervertebral foramen and extruded, mineralized disc material within the vertebral canal. Myelography is useful for evaluating the spinal cord and the cauda equina. Indication for myelography includes confirming a spinal lesion seen or suspected on survey radiograph, defining the extent of a survey lesion, finding a lesion not observed on survey radiograph, and distinguishing between surgical and nonsurgical lesion. In presentcases, two of three cases show radiographic signs of IVDD with survey radiograph and all of three case show extradural pattern during myelography. It is observed that intervertebral disc disease is one of the most important indication for radiographic examination and myelography of the vertebral column of small animals.