Fifty-nine subarachnoid hemorrhage with normal panangiography were reviewed (1982-1989). The mean age is 50 + 10. The grades at admission are compared following the Hunt and Hess and the World Federation Classification. Fifty cases (Hunt and Hess) or 45 (W.F.N.S.) are grade I or II. Compared with 278 cases of subarachnoid hemorrhage of aneurysmal etiology, 76% were in good grades versus 55% only for the aneurysms. Hypertension was present in 21 cases (35%) and represented a factor of gravity. Hydrocephaly is a rare complication in these cases and only 2 cases were shunted. The repetition of angiographic exploration seems to be unnecessary: all the examens remained negatives. The aspect on C.T. Scan was the same that the subarachnoid hemorrhage of aneurysmal origin. Angiography of 4 pedicles were performed in all cases and in the late 15 cases, external carotid explorations were added for exclusion of dural malformations. Seven suspected cases had had a secondary exploration between 12 days. The other cases were reexamined at 3 months. Three cases deceased from a second hemorrhage without aneurysm at autopsy. These cases confirm that subarachnoid hemorrhage of unknown etiology is of good prognosis. Low grades, rare complications, few rebleeding and good outcome scale are common. Etiology remains hypothetic.