Background : There has been no ideal valve prosthesis for children from the point of view of thromboembolism and size mismatch, and the surgical repair of native mitral valve has always been our first priority in children. However, valve replacement becomes the inevitable surgical option if repair is impossible. The purpose of this study was to assess the long-term results of mitral valvuloplasty (MVP) and mitral valve replacement (MVR) for isolated mitral valve diseases in children under 15 years old. Patients and Methods : From 1981 to 2010, 30 patients underwent a total of MVPs (P group) and 26 consecutive patients underwent a total of MVRs (R group). The median age was 4.6 years (4 months to 16 years) in group P and 6.2 years (4 months to 13.7 years) in group R, and the median body weight was 13.4 kg (6 to 35.5 kg) in group P and 16.4 kg (4.8 to 50.7 kg) in group R. The etiology was congenital in 55 (98%) patients, and due to endocarditis in 1 (2%) patient. Isolated mitral regurgitation was present in 41 (73%) patients (group iMR), and isolated mitral stenosis was present in 15 (27%) patients (group iMS). Mechanical valves (bileaflet disc, n=26) were used in all initial MVR patients. Results : Overall hospital mortality was 0%. The median follow-up time was 9.3±7.8 years (4 months to 27.7 years). There were 6 reoperations in P group and 5 explants due to size mismatch in R group with patient growth, and no explant due to structural valve deterioration. Survival rates at 10 years were 100% in the P group and 88.0% in the R group, and there was a significant difference (p=0.043). Freedom from reoperation at 10 years was 77.6% in P group and 77.0% in R group. Freedom rate from cerebral events at 10 years were 100% in both groups, respectively, and there were no significant differences. Survival rates at 10 years were 100% in the iMR group and 53.3% in the iMS group, respectively, and there was a significant difference between the groups (p<0.001). Freedom rates from reoperation at 10 years were 77.1% in the iMR group and 64.3% in the iMS group, respectively, there being no significant difference. Conclusions : The long-term results of pediatric mitral surgery were acceptable. Mitral valvuloplasty for patients with isolated mitral regurgitation were excellent. Mitral valve replacement can be performed with low initial mortality but should be reserved for medical and reconstruction failure because reoperation and late mortality are high, particularly for patients with isolated mitral stenosis.