Thoracic aortic rupture is a lethal injury associated with severe blunt trauma. Survival is directly related to early diagnosis and operative treatment. Establishing the diagnosis requires a high index of suspicion, recognition of radiologic evidence of mediastinal bleeding, and identification of injuries frequently associated with aortic rupture. A retrospective review of blunt trauma patients at the Washington Hospital Center Trauma Unit and data from the Major Trauma Outcome Study identified a two- to fivefold increase in the incidence of aortic injury among patients with pelvic fracture. Twenty to forty-five per cent of patients with aortic rupture had associated pelvic fracture.Our study documents that pelvic fracture is as reliable an indicator of associated aortic rupture as many currently accepted injuries. Its presence should raise suspicion for aortic injury.