A case of chondrosarcoma of the thoracic vertebra in a 47-year-old female is described. Chest X-ray, CT and MRI disclosed an abnormal mass lesion in the posterior mediastinum. The lesion was surgically removed through right thoracotomy. The operative findings revealed that the lesion, hard and measuring 6.5 x 4.5 x 4.5 cm in diameter, was originated from the 7th and 8th thoracic vertebra. The lesion was histopathologically diagnosed chondrosarcoma. The chondrosarcoma arising from the thoracic vertebra is very rare, and only 10 cases have hitherto been reported in the Japanese literature.