The incidence of sudden death due to undiagnosed primary intracranial tumor is low in forensic autopsy. We report a case of a 48-year-old white male, known to be a schizophrenic patient for several years, and in whom a medico-legal autopsy disclosed a large, previously undiagnosed, bilateral frontal glioblastoma infiltrating the genu of corpus callosum. We emphasize the importance of performing complete autopsy, including a thorough neuropathological examination, in all cases of sudden unexpected death, especially in those cases in which no extracerebral cause of death had been established and whose clinical history was primarily of a psychiatric nature.