A 73-year-old woman suffered from neck pain, progressive m tor weakness and sensory disturbance in all extremities. Neuroradiological studies revealed a retro-odontoid mass with posterior compression of the upper cervical spinal cord. Decompression of the mass was performed via a postero-lateral transdural approach, and the patient exhibited marked improvement of the symptoms. Histological examination revealed that the mass was composed of degenerative cartilaginous tissue, consistent with disc material, but the lesion was not neoplastic. Retro-odontoid disc herniation causing cervical myelopathy is very rare. We primarily discuss the surgical management of retro-odontoid disc herniation.