Sixty-four patients with suspected cystic myelopathy following spinal cord trauma were examined radiologically. In twenty-seven of these, spinal cord cysts were confirmed at surgery; in five, cysts were excluded by surgery and/or autopsy; the rest were unconfirmed. In water soluble myelography the most frequent sign in those with confirmed cysts was distention of the involved segments of the spinal cord. A less frequent but reliable sign was variation in cord size with position in a paradoxical fashion to the well established changes which occur with air myelography. Focal concentrations of contrast medium were visible within cord substance at CT in two of the patients in whom no cyst was found at surgery or autopsy. Some correlations between clinical features, including rate of progression and results of surgery, and radiological findings are unexpected on the basis of existing theories on pathogenesis.