An aortic aneurysm is defined as a pathologic dilatation to more than 1.5 times the normal diameter of the aorta. The prognosis is serious; several segments of the aorta can be dilated concomitantly. The wall of the aorta can be weakened by several processes: atherosclerosis, genetic predisposition (Marfan syndrome, Ehlers-Danlos syndrome type IV), infectious processes and trauma. The clinical course is asymptomatic in approximately 40% of patients, in the rest it can cause symptoms due to the pressure on periaortic structures. Thoracic aorta aneurysms are most commonly located in the ascending segment, then in the descending segment and most rarely in the aortic arch. We present a case of an isolated aortic arch aneurysm in 48-year-old man.