A retrospective study of 69 cases of infective endocarditis in 68 children (group I: 1971-1981; 34 children; group II: 1982-1992; 34 children) disclosed the following features: a moderate increase in the global incidence of infective endocarditis (0.5% of children hospitalized in paediatric cardiology units) and of its incidence in the very young (proportion of children less than 1 year of age: 9% in group 1 and 17% in group II); no rheumatic heart disease amongst predisposing heart diseases in children living in France; a major causal role of congenital heart diseases (72%), with an increasing incidence of previous operation (group I: 42%; group II: 56%); an increase in associated complex congenital heart diseases (group I: 11%; group II: 20%); no change in related mitral valve prolapse (5% in both groups); positive blood cultures in 76% of cases, with similar rates of Staphylococci (group I: 27%; group II: 30%) and of unusual microorganisms (15% in both groups); a major diagnostic role for echocardiography (vegetations in group II: 64%). Complications occurred in 75% of cases in both groups (pulmonary or systemic emboli, mycotic aneurysms, valvar regurgitation), leading to heart failure in 29% of group I patients and in 32% of group II patients. Mortality has decreased, from 12% in group I to 3% in group II, as a result of more frequent cardiovascular surgery (group I: 11 cases; group II: 15 cases), problems due to restrictive prostheses, and severe consequences: only 27% of group II children were cured without deterioration of their cardiac condition.(ABSTRACT TRUNCATED AT 250 WORDS)