The Lund Clinic serves a population of 1.46 million inhabitants. During the calendar year 1981, 72 patients presented with a ruptured supratentorial aneurysm, diagnosed either at angiography or at autopsy. Upon admission, 60% of the patients were in good condition and 40% were in poor condition. Eighty-three per cent were admitted within 72 hours after the subarachnoid hemorrhage (SAH). In the total series, 50% made a good recovery; the overall management morbidity was 19% and the management mortality was 31%. Thirty-one patients in Grades I-III underwent early operation (43% of the total series), with a favorable outcome in 74% and 7% mortality. Of the 35 patients who were admitted early and in good condition, 71% made a good recovery, and the management mortality was 9%. These figures may be compared to the 51% favorable outcome and 27% mortality reported from the Cooperative Aneurysm Study with late operation. In the early operation cases, the incidence of significant arterial narrowing at postoperative angiography performed on Day 9 +/- 2 after SAH was 30% and the incidence of permanent neurological deficits of delayed onset was 10%. Two of the early operation patients developed permanent symptomatic hydrocephalus.