Despite the progress in medicine, infectious endocarditis is often diagnosed late, as its symptomatology is subject to a high variability. The clinical features are usually atypical. Since the introduction of the Duke criteria, clinical, bacteriological and echocardiographical findings are being integrated, allowing an earlier definitive diagnosis. The incidence remains practically stable. The decrease in post-rheumatic valvular heart disease at population level is compensated by an increase in degenerative valvular heart disease as predisposing factor. Moreover, the share of patients with intravascular foreign material is increasing. Endocarditis is usually characterized by a complicated development. About half of the patients develop heart failure as a consequence of the destruction of the affected valve with serious valvular insufficiency. One third of the patients present cerebral or peripheral embolization. Embolization predominantly occurs at the beginning, until the first two weeks of antibiotic treatment. Abscess formation occurs more frequently than is suspected based on echographical examinations. Particularly a Staphylococcus aureus infection in the presence of an artificial valve leads to extravalvular extension with abscess formation around the artificial valve. Treatment should be initiated promptly. High doses of antibiotics, tailored to the microorganism and the valve type (native or artificial valve), are administered intravenously during four, or more frequently, six weeks. In more than half of the patients cardiac surgery is also required. As soon as an indication for cardiac surgery is present, the operation should not be postponed. Experience learns that a smaller risk is associated with an early intervention. The operation is performed in a technically easier way. Eventually, also the total duration of hospitalization is shorter. Despite the available antibiotics and the technical progress in cardiac surgery, mortality remains high. This is the consequence of an increasing share of aggressive hospital germs, on the one hand, and an older population, characterized by a higher comorbidity, on the other hand.