Spontaneous spinal epidural hematoma (SSEH) is an uncommon cause of acute nontraumatic myelopathy. We report a 14 year-old boy who had tetraplegia on awakening. Diagnosis of spinal epidural hematoma was made by magnetic resonance imaging. Despite spinal cord decompression within 9 h from onset, he remained tetraplegic. No cause for the bleeding was found. The pathogenic hypotheses of SSEH are discussed and the importance of rapid diagnosis and treatment is emphasized.