The authors examined 31 patients with moyamoya disease in Yugoslavia. Among them four intracranial aneurysms were disclosed, two in males and two others in females. The aneurysms, which were present in adult patients only, were diagnosed angiographically. Three of four patients died several days or weeks after onset of hemorrhage. The aneurysms were located within the basal abnormal vascular network, on a distal branch of the posterior cerebral artery, on the top of the basilar artery, and on the posterior branch of the middle meningeal artery. The moyamoya disease on the side of the individual aneurysms was most often stage III or IV.