35 cases of prosthetic valve endocarditis are reported. The diagnostic is based on clinical, echocardiographic, bacteriological and anatomical aspects. Heart failure, neurologic complications, positive culture of prosthesis, Staphylococcus aureus infection and perivalvular abscess are factors of a bad prognosis. The current therapeutic trends associate antibiotic treatment and infected prosthetic valve replacement rather for hemodynamic indications than bacteriological factors. General prognosis has a mortality of 40 p. cent. Prophylaxis of infection, although simple is necessary.