Twenty-five patients aged 31 to 74 years (average 50 years) operated for type A aortic dissection (type I: 19 cases, type II: 6 cases) were included in this study. Surgical repair only concerned lesions of the ascending aorta. The hospital mortality was 20 per cent (5 cases), and usually secondary to extension of the dissection. With the exception of 2 late deaths, all patients were followed up for an average of 3.5 years. A late assessment including nuclear magnetic resonance imaging of the thoracic aorta was obtained in 17 of the 18 survivors. These investigations confirmed the good result of repair of the ascending aorta, the uselessness of systematic aortic valve replacement and the palliative nature of repair of type I dissection as 80 per cent of patients had a persistent patent false lumen in the distal aorta.