Surgical aortic valve replacement is the sole validated treatment of aortic stenosis. The indications for surgery rely on risk/benefit ratio and on the official recommendations. A symptomatic patient with severe aortic stenosis should be submitted to surgery. The indication of valve replacement is more difficult in asymptomatic patients. The decision should integrate a combination of an exercise test and prognostic parameters associated with poor outcome. Most of them are obtained by Doppler echocardiography. Patients presenting with severe aortic stenosis and low transvalvular gradient constitute a subgroup of patients who require appropriate echocardiographic assessment to determine the potential benefit and risk of surgery. Transluminal aortic valve implantation is a new modality for patients at high surgical risk.