From 1972 to 1984, 104 cases of aortic valve infectious endocarditis were treated surgically. The average age of the patients was 40 years and the majority were men (69/104). Forty patients had no previous cardiac disease; 44 patients had documented valvular heart disease, which was unlikely in the remaining 20 patients. There were 16 mitral valve, 55 aortic valve, 1 tricuspid, 30 mitro-aortic, 1 mitro-tricuspid and 1 mitro-aorto-tricuspid valve infections. Aerococcus viridans was isolated in only 4 out of 71 positive cultures: the prevalence of the infecting organisms was otherwise normal (30 staphylococcus, 30 streptococcus, 7 rare organisms). Forty one patients were operated because of haemodynamic deterioration, 13 for resistant infection and 13 for an association of both indications; 37 patients were operated for embolism or threatening vegetations. Eight patients were in functional Class I, 26 in Class II, 52 in Class III and 17 in Class IV. The patients were divided into 4 groups according to the degree of surgical emergency (26 extremely urgent, 26 semi urgent, 32 controlled endocarditis and 20 chronic endocarditis). The actuarial survival rate was 70% at 5 years. Poor prognostic factors were the presence of previous valve disease, the isolation of a staphylococcus and an aortic valve localisation. The degree of emergency and the precise surgical indication did not seem to be important. Most patients at long term were in functional Classes I or II. There was no preferential indication for bioprosthetic or mechanical valve replacement in endocarditis.(ABSTRACT TRUNCATED AT 250 WORDS)