Spontaneous intraspinal intramedullary hemorrhage is a rare entity with the acute onset of neurologic symptoms. The etiology of idiopathic spontaneous hematomyelia (ISH) is unknown, and there are few published case reports. Hematomyelia is mostly associated with trauma, but the other nontraumatic etiologies are vascular malformations, tumors, bleeding disorders, syphilis, syrinx, and myelitis. MRI is a good choice for early diagnosis. Hematomyelia usually causes acute spinal cord syndrome due to the compression and destruction of the spinal cord. A high-dose steroid treatment and surgical decompression and evacuation of hematoma are the urgent solution methods. We present idiopathic spontaneous hematomyelia of a previously healthy 80-year-old male with a sudden onset of back pain and paraplegia.