In this paper, two cases with mature teratoma of the lateral ventricle are presented. Teratomas are rare intracranial tumours and the most common location is in the midline pineal region. Lateral ventricle as the site of location is very rare. Between the years 1975 and 1996, 120 cases were operated on for lateral ventricle tumours at the University of Ankara, Department of Neurosurgery, and only two cases (% 1.6) were histologically identified as mature teratomas. It is generally accepted that benign teratomas are radioresistant and total removal of these tumours results in cure. If mature teratoma of the lateral ventricle is totally removed, as done in our cases, the prognosis is usually good.