Blunt abdominal aortic injury is an extremely rare and fatal condition. Hemothorax with bleeding from an extrathoracic organ is also an extremely rare condition. Studies have reported abdominal aortic aneurysm and renal trauma but not hemothorax following blunt abdominal aortic injury. We examined a 52-year-old woman with abdominal pain caused by seatbelt injury. She was close to experiencing cardio-pulmonary arrest. We performed a lateral thoracotomy and clamped the descending thoracic aorta.