Aortic stenosis is a condition in which progression accelerates with the onset of warning symptoms such as angina pectoris, syncope and heart failure. Surgery must be scheduled as quickly as possible in all such symptomatic patients, even in the presence of concomitant coronary disease, or of left ventricular failure. Aortic valve surgery is possible in the elderly, with a higher operative risk, but with the benefit of a symptomatic improvement identical to that seen in younger individuals, and a prolongation of life expectancy. Surgery is often considered in asymptomatic patients because of the fear of sudden death. In actual fact, sudden death not preceded by other symptoms is rare and the aim of surveillance must be to identify high-risk patients to whom surgery may be offered: poor exercise tolerance in a cautiously administered exercise test, abnormal ventricular function by echocardiography, or the existence of arrhythmias, which are also a severity factor, whether atrial or ventricular. The number of completely asymptomatic cases among patients with tight aortic stenosis is relatively slight, having been evaluated at 5%. It is in these asymptomatic patients, when they are young, that it is possible to delay surgery until the onset of a first symptom.