In order to update our information about the incidence and demographic, microbiological and clinical characteristics of infective endocarditis (IE) in France, a 12 month long study was carried out in three regions: Ile de France, Rhône-Alpes and Lorraine. Four hundred and fifteen cases of IE were recensed: certain (32%), probable (53%) or possible (15%). The annual incidence was 24.3 per million. The average age was 56 +/- 19 years. There was no past history of cardiac disease in 34% of cases; 33% had native valvular heart disease and 22% had one or more valvular prostheses. The site of IE was mitral in 39%, aortic in 36%, tricuspid in 6% and other or multivalvular in 19% of cases. The causal microorganism was isolated in 92% of cases. It was a streptococcus in 58% of cases (S. viridans in 27%; group D streptococcus + enterococcus in 23%); a staphylococcus was isolated in 23% of cases (Staphylococcus Aureus in 18%) and another microorganism in 11% of cases. The presumed portal of entry was dental in 24%, gastro-intestinal in 13%, cutaneous in 6% and urinary in 4% of cases. Twenty patients were intravenous drug addicts. Forty-five patients had medical or surgical procedure. Twenty-four per cent of patients were operated during the first two months, 17% died during this period (15% of operated and 18% of non-operated patients). Despite the advances in antibiotic therapy and in cardiac surgical techniques, IE seems to be as common and as severe as ten years ago.(ABSTRACT TRUNCATED AT 250 WORDS)