Echocardiography is the key examination in the assessment of mitral and aortic regurgitation, as it is able to describe the etiology and mechanism of the disease and assess its severity and its repercussions on cardiac cavities and pulmonary pressures. Surgery now tends to be indicated at earlier stages, largely based on criteria drawn from echocardiography. In severe mitral regurgitation, surgery is not disputed in presence of left ventricular ejection fraction < 60% and/or end-systolic diameter > 45 mm. In a selected group of patients aged < 75 years, with a very high likelihood of successful repair and a low operative risk, surgery should be considered earlier (if ejection fraction is > 60% and end-systolic diameter < 45 mm) in degenerative regurgitation such as flail leaflets. In aortic regurgitation, surgery should be considered in presence of an acceptable operative risk as soon as end-systolic diameter exceeds 25 mm/m2 (and/or end-diastolic diameter > 70 mm) or resting ejection fraction < 55%. Surgery should be performed rapidly in dystrophic aortic regurgitation, independent of its severity, if the diameter of the ascending aorta exceeds 50 or 55 mm, or if it increases rapidly during follow-up. Echocardiography is therefore at the center of the strategic discussion concerning the indication for and timing of surgery.