Giant cell arteritis (GCA) is an autoimmune disease characterized by granulomatous inflammation in the wall of medium-sized and large-sized arteries, and it usually occurs in patients over 50 years of age.(1)) Symptoms are nonspecific, and include fatigue, fever, and headache.(2)) It is occasionally combined with aortic complications, and ruptures resulting in death. These complications occur as late events, usually several years after diagnosis and often after other symptoms have subsided.(3)) Physicians should therefore be alert for complications of the large arteries in GCA. Here we present a case of GCA combined with ascending aortic dissection and rupture 3 weeks after diagnosis.