The presence of cartilage in a glial tumor is exceptional. It frequently occurs in ependymoma of midline location in young child nuder 5 years of age. The mechanism of cartilage and bone formation in ependymoma is thought to be either metaplastic transformation from mesenchymal tissue or direct transformation from the neoplastic glial cells. A case of ependymoma containing cartilage and bone is reported. The patient is a 4 year-old girl, having calcified mass in the 4the ventricle and cerebellar vermis. The pathogenesis of cartilage formation in this ependymoma is more likely to support the mataplastic theory.