Significant neuropsychologic sequelae were induced by total removal of craniopharyngioma via a frontobasal interhemispheric approach. A 50-year-old right-handed man developed severe amnesic syndrome and collecting behavior after total removal of a craniopharyngioma. He had very poor results on tests of learning, recall, and recognition for both verbal and nonverbal tasks. Magnetic resonance imaging revealed damage to the bilateral mammillary bodies and fornices, and N-isopropyl-p-[23I]iodoamphetamine single photon emission computed tomography showed decreased cerebral blood flow in the bilateral frontal lobes, predominantly in the right, and regions around the third ventricle. The present case suggests that damage to the brain structures surrounding the third ventricle associated with surgery for craniopharyngioma may result in amnesic syndrome and collecting behavior. Generally, the frontobasal interhemispheric approach is the optimum choice for the removal of craniopharyngioma without significant sequelae related to the surgical method, but the risk of neuropsychologic disturbances must be kept in mind.