The hospital records of patients treated with ruptured abdominal aortic aneurysm in a recent 5-year period were reviewed to collect data on factors which may be associated with mortality. Overall mortality was 62%. Patients with intraperitoneal rupture had a higher mortality (97%) than patients with retroperitoneal rupture (25%). Patients at increased risk were older than 80 years, presented with syncope, experienced a short duration of symptoms prior to emergency department (ED) arrival, had initial systolic blood pressure less than 90 mm Hg, and/or initial hemoglobin level less than eight on arrival at the ED and delay in beginning surgery. Multivariate analysis demonstrated preoperative blood pressure, preoperative hemoglobin, presence of syncope, and the amount of blood transfused were largely reflections of the type of rupture and had only slight independent relationship to mortality. The authors concluded that treating emergency physicians and surgeons have little control over the most important risk factors for mortality after aneurysm rupture, but may improve the prognosis by expediting diagnosis in the ED and surgical therapy.