Blunt traumatic aortic injury is a rare but life-threatening condition, usually following high-energy trauma. We present the case of a 79-year-old man who was transferred to a hospital complaining of nausea after being struck on the chest. Computed tomography led to diagnosis of ascending aortic dissection with cardiac tamponade. Emergent ascending aortic replacement was performed successfully and he was discharged home on postoperative day 24 without any complications. The key to early diagnosis of blunt traumatic aortic injury is careful and detailed history-taking. If trauma patients complain of unexplained symptoms, the threshold for conducting computed tomography should be lowered to avoid misdiagnosis or therapeutic delay.