The long-term evaluation of 60 patients who suffered a subarachnoid hemorrhage and survived 6 months is reported. By bilateral carotid arteriography, all patients were shown to have a single aneurysm at the vicinity of the posterior communicating artery at its junction with the internal carotid artery. The patients had previously been randomly assigned to treatment either by bed rest or by common carotid ligation. Average duration of survival among those followed is 8 years. Late rebleeding episodes were found to occur at a similar rate, irrespective of mode of treatment in the studied populations, but morbidity following operation continued to remain somewhat less over the ensuing years of follow-up study compared with the patients treated conservatively. On final assessment many years after the original hemorrhage, there is little improvement in degree of morbidity in either treatment group, and hypertension is noted to develop in the patients undergoing carotid ligation. A larger number of cases will be required to validate these findings.