Background: The 2014 Guidelines for the Management of Patients with Valvular Heart Disease require to know the probability of success and operative mortality of Mitral Valve Repair (MVR) for Degenerative Mitral Insufficiency (DMI) at a given institution. Aim: To assess the probability of success, operative mortality and long-term results of MVR for DMI. Patients and methods: The database of the Cardiovascular Surgery Service was reviewed for the period December 1991 to December 2013. Long-term survival information was obtained from death certificate records of the Chilean Identification Service. Results: One hundred forty seven patients with DMI were identified, all operated by one author (RZ). In 28 (19%) the mitral valve was replaced, including three patients in whom a MVR was intended without success. A successful MVR was performed in 119 patients (81%). The probability of a successful MVR was 97.5% (119 of 122). Prolapsed posterior leaflet was present in 81% and annulus dilatation in 60% of cases. The most frequent surgical procedures were quadrilateral resection (83%) and chordal transfer (13%). A mitral annuloplasty was performed in 92% of cases. Operative mortality was 0.8%. At the end of a 9.9 (0 – 22.7) years follow-up, 87 patients (73%) were alive and mean survival was 16.9 years. Survival rates at 5, 10, 15 and 20 years were 91%, 78%, 71% and 50%, respectively. Six patients were re-operated, due to mitral valve dysfunction in three. Mean re-operation free survival was 21.4 years. Echocardiographic follow-up was 75% completed at an average of 64 months; 84% of cases had no or only 1+ mitral regurgitation. Conclusions: In our experience, MVR for DMI had an operative mortality below 1% and a probability of success greater than 95%, with excellent long-term results.Background: The 2014 Guidelines for the Management of Patients with Valvular Heart Disease require to know the probability of success and operative mortality of Mitral Valve Repair (MVR) for Degenerative Mitral Insufficiency (DMI) at a given institution. Aim: To assess the probability of success, operative mortality and long-term results of MVR for DMI. Patients and methods: The database of the Cardiovascular Surgery Service was reviewed for the period December 1991 to December 2013. Long-term survival information was obtained from death certificate records of the Chilean Identification Service. Results: One hundred forty seven patients with DMI were identified, all operated by one author (RZ). In 28 (19%) the mitral valve was replaced, including three patients in whom a MVR was intended without success. A successful MVR was performed in 119 patients (81%). The probability of a successful MVR was 97.5% (119 of 122). Prolapsed posterior leaflet was present in 81% and annulus dilatation in 60% of cases. The most frequent surgical procedures were quadrilateral resection (83%) and chordal transfer (13%). A mitral annuloplasty was performed in 92% of cases. Operative mortality was 0.8%. At the end of a 9.9 (0 – 22.7) years follow-up, 87 patients (73%) were alive and mean survival was 16.9 years. Survival rates at 5, 10, 15 and 20 years were 91%, 78%, 71% and 50%, respectively. Six patients were re-operated, due to mitral valve dysfunction in three. Mean re-operation free survival was 21.4 years. Echocardiographic follow-up was 75% completed at an average of 64 months; 84% of cases had no or only 1+ mitral regurgitation. Conclusions: In our experience, MVR for DMI had an operative mortality below 1% and a probability of success greater than 95%, with excellent long-term results.