Nine patients whose history suggested increased intracranial pressure (ICP), but whose funduscopic examination did not reveal papilledema, are described. Cerebrospinal fluid monitoring in seven of the cases showed abnormal pressure waves ranging from 22 to 40 mm Hg. The findings of computed tomography and isotope cisternography and the response to therapy supported the clinical diagnosis of benign intracranial hypertension (BIH). Fluorescein angiography, which was performed in five cases, was normal. None of the patients had enlargement of the blind spot; all had normal intraocular pressure. The clinical spectrum of BIH may need to be enlarged to include cases of increased ICP without clinically evident papilledema. (Neurosurgery, 7: 326-336, 1980).