Review of a series of 460 patients with spontaneous intracranial hemorrhage showed that 241 had demonstrable aneurysms and 38 had multiple aneurysms. The importance of demonstrating the entire circulation following ligation of one aneurysm is emphasized. Treatment of the 38 patients with multiple aneurysms is described. Ligation of unruptured aneurysms that are incidentally discovered is advocated in patients who are Grade 1 on the Botterell scale and who are well informed as to the risks.