OBJECTIVES: This study aimed to evaluate risk factors that affect mitral valve (MV) repair outcomes. METHODS: From 2002 to 2012, 580 consecutive patients with mitral regurgitation (MR) underwent MV repair. Of the total number of patients, 48.9% were found to be in New York Heart Association (NYHA) Class III or IV. Anterior, posterior and bileaflet prolapse was present in 34.8, 47.6 and 17.6% of patients, respectively. Atrial fibrillation (AF) was found in 29.7% of patients. The mean follow-up was 5.3 +/- 2.6 years. RESULTS: There were eight early and 14 late deaths. NYHA Class III/IV, left ventricular ejection fraction <= 50%, systolic pulmonary artery pressure >= 50 mmHg, AF and low cardiac output syndrome with extracorporeal membrane oxygen were independent predictors of early mortality. AF, NYHA Class III/IV, left ventricular end-systolic diameter >= 40 mm and systolic pulmonary artery pressure >= 50 mmHg remained predictors of late mortality. At 5 years, the rate of survival, freedom from reoperation and recurrent moderate to severe MR was 99.0 +/- 0.6 97.2 +/- 0.8 and 93.3 +/- 1.2%, respectively. Anterior leaflet involvement was predictive of reoperation and recurrent moderate to severe MR. In patients with a moderate tricuspid regurgitation (TR) and annulus <40 mm, the degree of TR during follow-up was worse with right ventricular dilatation. CONCLUSIONS: MV repair should be performed before the deterioration of ventricular function, development of pulmonary hypertension and AF occurrence. The pathophysiology of MR affects MV repair durability, while concomitant tricuspid annuloplasty should be considered in patients with moderate TR despite annular dilatation.