Objective:To investigate the surgical procedure for mitral valve prolapse complicated by infective endocarditis.Methods: From June 2000 to December 2007,40 patients with mitral valve prolapse complicated by infective endocarditis received operation in our hospital.The patients included 30 males and 10 females,with a mean age of 39.2 years (ranging 13-63 years).The positive blood culture rate was 42.5% before operation.Combination of echocardiogram with post-operative pathology was the main method for diagnosis.The grades of cardiac function of the patients were in NYHA Ⅱ(15 cases),Ⅲ(21 cases)and Ⅳ(4 cases).Mitral valve repair was performed in 5 patients and mitral valve replacement was done in 35 cases,all with artificial mechanical heart valves.Results: One patient died of renal failure early after operation.One patient had complete AV block and received pacemaker implantation.All the patients had normal body temperature on discharge.During follow-up (mean 2.7 years,ranging 6 months to 8 years),39 patients survived without later mortality,recurrence of endocarditis and paravalvular leakage.Conclusion: Surgical treatment for patients with mitral valve prolapse complicated by progressive moderate or severe mitral regurgitation and infective endocarditis should be performed as early as possible.Radical debridement of the infected tissues and application of sensitive and high dose of antibiotics are the keys for preventing postoperative endocarditis recurrence.Replacement or annuloplasty should be chosen according to the quality of the valve during surgery.The results of mechanical prosthetic valve are excellent.