Spontaneous intracranial hypotension is frequently idiopathic. The authors report on a patient presenting with symptomatic intracranial hypotension caused by a transdural calcified thoracic disc herniation. Cranial magnetic resonance (MR) imaging revealed classic signs of intracranial hypotension, and a combination of spinal MR and computerized tomography myelography confirmed a mid-thoracic transdural calcified herniated disc as the cause. The patient was treated with an epidural blood patch and burr hole drainage of the subdural effusion on two occasions. Postoperatively the headache resolved and there was no neurological deficit. Thoracic disc herniation may be a cause of spontaneous intracranial hypotension.