Thoracic disc herniation is uncommon. One of the main problems in the treatment of thoracic disc herniation has been the lack of accuracy of diagnostic tests. Now, with the use of computed tomographic scanning with and without metrizamide in the subarachnoid space, this accuracy has greatly improved. Computed tomography scanning can demonstrate the type and level of the lesion even when the myelographic study is negative. We have reviewed 280 cases; a peak incidence was noted in the fourth decade with 75% of the protruded discs occurring below T-8. Back pain was the most common presenting symptom followed by sensory disturbances. By the time of diagnosis, 70% of the patients had signs of spinal cord compression. A small group of patients could be identified that invariably had a good prognosis. They had a history of trauma, symptoms lasting less than a month, and soft disc herniation. Regarding the results of surgical treatment, there was a success rate ranging from 57% for decompressive laminectomy to over 80% for the posterolateral, lateral, and transthoracic approaches.