Infectious endocarditis (IE), an infection of heart valves or intracardiac implants, is a rare disease with high mortality. Predisposing factors include congenital defects, degenerative valve changes, and cardiac implants. The diagnosis is often difficult due to very different clinical presentations. Therefore, imaging, especially echocardiography, and blood cultures have a central role in the diagnosis. The most common pathogens of IE are Staphylococci, Streptococci, and Enterococci. The therapy is carried out with antibiotics as part of a long-term therapy; in about half of the cases, surgical sanitation is necessary. An indication for surgery exists in the development of heart failure, lack of control of the infection by antibiotics, and to prevent embolisms.