We report a case of a patient with large intraventricular tumor treated with craniotomy assisted by a neuroendoscope. A 25-year-old man, who had headache and nausea for several months, was transferred to our hospital with the diagnosis of an intraventricular tumor. Because of intracranial hypertension and hydrocephalus, we first performed a biopsy and bilateral intraventricular drainage using a neuroendoscope. Since the pathological finding indicated central neurocytoma, we secondarily attempted tumor removal. The main location of the tumor was the left lateral ventricle, protruding into the third ventricle and contralateral lateral ventricle. The operation was performed mainly under microscopic visualization through left-sided craniotomy, and the total excision was accomplished using a neuroendoscope through the right lateral ventricle. In order to accomplish the optimal removal of an intraventricular tumor, endoscope-assisted microsurgery should be considered a surgical strategy.