In 10,995 consecutive medicolegal autopsies, there were 19 deaths due to an unsuspected primary intracranial neoplasm. Nine (47.4%) of the tumors were in the astrocytoma glioblastoma category. The remainder included four cases of oligodendroglioma and one case each of medulloblastoma, microglioma, meningioma, teratoma, colloid cyst and pituitary chromophobe adenoma. In six cases, death occurred following abrupt loss of consciousness, or else the patient was found dead. In five of these six cases, there were no known preceding symptoms. The remaining 13 patients exhibited the characteristic symptoms produced by intracranial neoplasms, including symptoms of increased intracranial pressure, epilepsy, and psychiatric manifestations. Only one patient presented with a focal neurologic deficit which resolved in 24 hours. A comparison of the duration and type of symptomatology exhibited by these patients with a hospital patient population in which death was caused by a previously diagnosed primary intracranial neoplasm and an autopsy was performed underscored 1) the shorter duration of acute symptomatology, 2) the nonlocalizing nature of the symptoms manifested, 3) the lack of progression or change in symptoms in those patients in whom epilepsy was the primary manifestation of their underlying disease, and 4) the lower incidence of focal neurologic deficits as the presenting symptoms in our series.