OBJECTIVE Repair of bileaflet prolapse has been considered to be technically demanding and challenging. To assess the reliability and durability of mitral valve repair for bileaflet prolapse, the present study compared the outcomes of mitral valve repair for bileaflet prolapse with those for posterior prolapse. METHODS From January 1991 to April 2010, 191 consecutive patients with bileaflet prolapse (group B) underwent mitral valve repair using a combination procedure of expanded polytetrafluoroethylene chordal reconstruction for anterior prolapse, resection suture technique with/without sliding technique for posterior prolapse, and ring annuloplasty. During the same period, 323 patients with posterior prolapse (group P) underwent standard mitral valve repair. Serial echocardiograms were obtained at discharge and 1, 3, 5, and 10 years postoperatively. RESULTS The mean age in group B (54 ± 15 years) was significantly younger than that in group P (61 ± 12 years). Survival, including hospital death at 10 years, was superior in group B (group B, 90% ± 3%; group P, 83% ± 3%; P = .046). At 10 years, no significant differences were found between the groups in terms of freedom from recurrent mitral regurgitation of more than mild (group B, 89% ± 3%; group P, 90% ± 2%), freedom from reoperation (group B, 97% ± 2%; group P, 97% ± 1%), and event-free survival (group B, 79% ± 5%; group P, 83% ± 3%). CONCLUSIONS The reproducibility and reliability of mitral valve repair for bileaflet prolapse compares favorably with that of posterior leaflet prolapse. Early surgery might be recommended for patients with severe mitral regurgitation owing to bileaflet prolapse.