Two patients with intraventricular tumours are presented. Both had similar features on light microscopic examination. On the basis of the specific immunohistochemical staining patterns and the ultrastructural findings, one was diagnosed as a central neurocytoma while the other was diagnosed as an intraventricular oligodendroglioma. The possibility of central neurocytoma should be considered in all young patients including children presenting with an intraventricular lesion. Definitive diagnosis requires electron microscopic and immunohistochemical studies.