The hospital records for patients treated for ruptured abdominal aortic aneurysms in southern West Virginia during a recent five year period were reviewed. The over-all mortality rate was 62 per cent. Patients with intraperitoneal rupture had a higher mortality rate (97 per cent) than patients with retroperitoneal rupture (25 per cent). Patients at increased risk were more than 80 years of age, presented with syncope, experienced a short duration of symptoms before seeking medical attention, had preoperative systolic blood pressure levels of less than 90 millimeters of mercury and had a preoperative hemoglobin level of less than 8. Other factors associated with death were a delay in beginning surgical treatment, a larger total blood loss and amount of blood transfused. The results of multivariate analysis demonstrated that preoperative blood pressure, preoperative hemoglobin, presence of syncope and the amount of blood loss were, in large part, reflections of the type of rupture and had only slight independent relationship to mortality. The most effective method of preventing fatal outcome is elective resection of the aneurysms before rupture occurs.