There has been great progress during the past decade in management of patients with mitral regurgitation. Doppler echocardiography allows accurate quantification of the degree of valve leakage and tracking of the effect of regurgitation on cardiac size and function. Natural history studies have clearly delineated the deleterious effects of severe, persistent mitral valve regurgitation including an increased risk of cardiac death as well as a predisposition to the development of congestive heart failure and atrial fibrillation. In virtually all of our analyses, short-term and long-term outcomes are improved in patients who have early surgical correction of severe mitral valve regurgitation. Moreover, there are clear benefits of mitral valve repair over valve replacement, including greater regression of left heart dimensions, normalization of left ventricular function, and superior long-term survival.