Aneurysmal dilatation of the aortic root occurs in some patients with tetralogy of Fallot (TOF) late after repair. It can lead to aortic valve insufficiency and rarely to aortic rupture or dissection. Aortic valve or aortic surgery is rarely performed in this group of patients. We present a case of aneurysmal dilatation of the ascending aorta treated with aortic valve sparing root replacement 43 years after the TOF repair. Histological examination of the aortic wall revealed medial necrosis. The implications of those finding and the timing of surgery are discussed.