The authors report 4 cases of aortic dissection after aortic valve replacement. The aorta was dilated in all four cases before surgery. Two patients died within hours of the dissection, illustrating the poor prognosis of this complication and the difficulties of surgical management. The features of these four cases were compared to those of 29 other cases reported in the last ten years. The initial surgical indication for valve replacement was equally divided between aortic stenosis and regurgitation. The onset of dissection after surgery was very variable, ranging from a few hours to several years after valve replacement. Abnormalities of the aortic wall and peroperative trauma play an important role in the pathogenesis of this complication. The prognosis is very poor, which underlines the importance of preventive measures and regular follow-up of these patients.