The study included 38 patients with intracranial aneurysms, whose close relatives had experienced intracranial hemorrhages. The patients' relatives were divided into 2 groups according to the verification of the source of hemorrhage. The individuals at risk for aneurysmal disease in whom aneurysms should be sought before their rupture were examined. The patients with familial aneurysms were found to tend to rupture at younger age than those without familial aneurysms (the so-called sporadic aneurysms). The high rates of mortality due to intracranial bleeding were observed among the relatives of patients from the study group. Screening study of the first-order relatives of the patients with prior aneurysmal subarachnoidal hemorrhage is the method of choice in detecting unruptured cerebrovascular aneurysms. Early detection and switching-off of asymptomatic aneurysms may reduce mortality and disability rates in this group of patients.