An 88-year-old man was transfered to our hospital due to loss of consciousness. Intravenous dopamine was initiated for a shock status and endotracheal intubation was performed. Computed tomography with contrast medium showed Stanford type A acute aortic dissection complicating cardiac tamponade. Because cardiac drainage was not effective, we performed an emergent operation. Intrapericardial cavity was filled with clotted blood. Prosthetic graft replacement of ascending aorta was performed successfully under deep hypothermic circulatory arrest. His clinical course was uneventful and he was discharged on foot without any neurologic deficits.