We have reviewed 108 cases of bacterial endocarditis treated surgically since 1968. The mean age of the patients was 47.7 +/- 15.6 years (+/- SD) (range, 14-79 yr). Seventy-seven percent were male. The most common causative organisms were staphylococci (46%), streptococci viridans group (5%), and other streptococci (20%). Forty-five percent, 25%, and 13% of patients had native aortic valve, native mitral valve, or native double valve (AV/MV) involvement, respectively. Eighteen patients had prosthetic valve endocarditis. No patient underwent surgery for tricuspid valve endocarditis. Seventy-three patients were considered to have active endocarditis (AE) (positive blood or tissue cultures and/or annular abscess). The 35 remaining patients had healed endocarditis (HE). Preoperative complications in patients with either AE or HE were stroke (11%, 11%), renal failure (33%, 3%; p less than 0.001), pulmonary edema (83%, 34%; p less than 0.001), anemia (36%, 8%; p less than 0.01), and inotrope dependence (22%, 6%; p less than 0.05). Hospital mortality for native valve AE was 19.5% (11/56), and for healed endocarditis, 5.7% (2/35). Independent predictors of hospital mortality were inotrope dependence (p less than 0.001), annular abscess (p less than 0.01), pulmonary edema (p less than 0.01), and staphylococcal infection (p less than 0.05). The 5-year actuarial survival for operative survivors was 68.4 +/- 7.5% (AE) and 78.3 +/- 9.2% (HE). We conclude that the operative mortality for patients with continuing sepsis is high and that surgery should be undertaken early in staphylococcal endocarditis. If surgery is successful, then the long-term prognosis is good.