The mortality rate, risk of rebleeding, relevant subjective and objective symptoms, and daily functional capacity after a verified subarachnoid hemorrhage (SAH) of unknown etiology were evaluated in 44 patients treated during a 5-year period (1978 to 1983). A vascular basis for the SAH had been excluded by bilateral carotid and vertebral angiography and computerized tomography. The patients were interviewed at a follow-up examination from 3 to 64 months (median 36 months) after the bleed. The results revealed a 5% mortality rate and a 7% risk of rebleeding. Persisting headache and fatigue were found in 40% of patients, 29% had mild demential symptoms, and 5% had persisting and severe objective neurological symptoms. None had developed epilepsy. A normal daily functional capacity was enjoyed by 84%, while 14% had a moderate reduction in these functions, but were independent of help from other persons. One patient (2%) was not fully assessed.