Nontraumatic spinal subdural hematomas secondary to anticoagulants are remarkably rare. A case of spontaneous, atraumatic subdural hematoma involving the thoracic region in an 80-year-old woman on warfarin is reported. The patient presented with gross motor and sensory loss, delayed onset of incontinence, and no other symptoms. An MRI suggested an epidural hematoma concentrated around the T4-T9 levels. She was taken emergently to the OR approximately 30 hours after the initial onset of symptoms for a T3-T11 laminectomy. No epidural hematoma was noted. However, discoloration and bulging of the thecal sac were noted, and the dura was incised longitudinally from T2 to T10 revealing an expansive jelly-like blood clot which was evacuated. Postoperatively, the patient had regained 1/2 sensory function in the bilateral lower extremities. At the 2-week mark, the patient was still incontinent and showed 2/2 sensory and 2/5 motor functions in select muscle groups in her bilateral lower extremities. Completely nontraumatic, spontaneous subdural hematomas of the spine are very rare, and early surgical decompression within 24 hours from symptom onset may allow neurological recovery. Large extensive laminectomies up to 10 thoracic levels have been shown to be safe and effective in a few cases, including our case.