A recently reported group of patients with intracranial aneurysms, operated upon by the direct approach, resulted in a mortality of 45%. Only 62% of these consecutively treated patients had previous angiography. In a larger group of 75 patients with angiographically localized aneurysms, 58 of whom had "planned" operation, a mortality of 20.7% obtained. In the direct attack on the aneurysms,a total mortality of 19.5% was achieved. Factors influencing the mortality included time of operation following subarachnoid hemorrhage; presence of intracerebral hematoma and exact angiographic localization.