A 54-year-old man presented with an extremely rare case of intervertebral disk herniation with hematoma in the thoracic spine, manifesting as acute progressive numbness and muscle weakness in the bilateral lower extremities. He had been treated with anticoagulants. Magnetic resonance imaging of the thoracic spine showed intervertebral disk herniation and severe compression of the spinal cord at T9-10, appearing as hyperintense on T(1)- and hypointense on T(2)-weighted imaging suggestive of concomitant hematoma. His symptoms completely resolved after resection of the brownish herniated disk material. Old hemorrhage was also aspirated from the intervertebral disk space. Hemosiderin deposition was found in the cartilaginous tissue of the resected disk. Intervertebral disk herniation with hematoma is extremely rare, but may occur in patients with bleeding diathesis.