A 54-year-old man presented with sharp chest pain and hypertension. He was treated with intravenous antihypertensive with good control of the blood pressure. Chest X-ray showed widened mediastinum, and subsequent computed tomography scan of the chest demonstrated dissection of the descending thoracic aorta. It also showed an aberrant right subclavian artery with retrograde extension of dissection and Kommerell's diverticulum, which is dilatation at the origin of the aberrant subclavian artery.