Surgery is the only definitive therapy for severe mitral regurgitation (MR) and the guidelines recommend surgery for management of MR to symptomatic patients or asymptomatic patients with left ventricular (LV) dysfunction. However, the timing of surgical intervention in asymptomatic patients with severe MR remains unclear due to the lack of randomized clinical trials comparing early surgery versus watchful waiting. The benefit of early surgery has been suggested in prospective, observational studies, whereas a watchful waiting strategy seemed to be safe and effective in the other prospective study. The consensus guidelines for the performance of early surgery in asymptomatic patients with severe MR are different, reflecting controversy. The 2006 American College of Cardiology/American Heart Association (ACC/AHA) guidelines recommend early surgery for asymptomatic patients if the success rate of mitral valve repair is expected to exceed 90%, but the 2007 European Society of Cardiology (ESC) guidelines recommend watchful waiting for such patients.