Between 1983 and 1991, 104 patients (average age: 52 +/- 13 years) with aortic endocarditis (94 on native and 10 on prosthetic valves), were operated, 81 before the end of antibiotic therapy. Blood cultures were negative in 17 patients, identified a streptococcus in 49 patients, a staphylococcus in 16 patients, and a Gram negative or other organism in 22 patients. The following complications were observed before surgery: severe cardiac failure in 67 patients, renal failure in 24 patients, conduction defects in 13 patients, neurological complications in 13 patients, systemic or coronary embolism in 12 patients. Aortic valve replacement was performed in all patients, associated with mitral valve replacement in 25 patients and tricuspid valve replacement in 1 patient. Twelve patients died after surgery (11/81 of early operations, 1/23 operated later; NS). During a follow up of 3.5 +/- 2.8 years, there were 24 late deaths, 12 of non cardiovascular causes. Of the 20 variables tested, 3 were related to perioperative and late mortality (age, cardiac and renal failure). The 5 year survival (58.1 +/- 5.7%) is identical to that of the period 1970-1982 despite a very significant drop in perioperative mortality. Some of the causes of late mortality (older age of patients, changes in the infecting organisms) provide little hope of improving the prognosis in the near future. Others suggest that earlier surgery could improve the long term prognosis.