A primary intraspinal primitive neuroectodermal tumor is very rare, with only 24 cases having been reported in the literature. In general this type of tumor is treated with surgery followed by radiotherapy and chemotherapy; however, the prognosis still remains poor. The case of a primary intraspinal primitive neuroectodermal tumor, at the conus medullaris in a 17 year old male patient is presented. He had sufferred from paraparesis, urinary difficulty and lower back pain of 1 month duration. A thoracolumbar MRI demonstrated a 2×2×8cm isointense intraspinal mass, on T1-weighted images, with strong contrast enhancement from the T11 to L2 level. There was no clinical or radiological evidence for the existence of an intracranial tumor. A histological examination revealed a small round cell tumor and immunohistochemical characteristics of PNET. The clinical, radiological and pathological features are discussed with a review of the literatures.