A case of osteoid osteoma in the left lamina of the T-8 vertebra is reported. The roentgenograms of the thoracic spine showed a hyperostotic round mass with associated scoliotic changes and the myelograms revealed complete obstruction of the spinal subarachnoid space. By selective spinal angiography a peculiar ring-like vascular stain was visualized in the area of hyperostosis which may be characteristic of an osteoid osteoma.