An aneurysm is a permanent localized dilatation of an artery. A trauma is a rare cause of aortic aneurysm. The prognosis of untreated thoracic aneurysm is poor, with 3-year survival rates as low as 25%. Factors that seem to worsen the prognosis are female gender, size greater than 6cm, and traumatic origin. Because of the poor prognosis for the untreated patient and inability to predict rupture, surgical treatment of thoracic aortic aneurysms that result from trauma, even when asymptomatic is justified. The case of a 29 year-old patient, with post-traumatic aortic arch aneurysm qualified for delayed surgery treatment, is presented.