We experienced a craniopharyngioma in the third ventricle which was removed totally by a staged operation through the lamina terminalis and then through the foramen of Monro using a transventricular approach. In magnetic resonance imaging, chiasmal thickening with pot-belly expansion and bilobed shape of the mass were found, and postoperative magnetic resonance imaging showed indentation of the chiasm and flattening of the floor of the third ventricle.