From 1972 to 1982, 22 patients were admitted for prosthetic valve endocarditis on homografts (3), bioprostheses (2) or mechanical prostheses (17). Staphylococcus epidermidis was the most common aetiologic agent in early-onset endocarditis and streptococci in late-onset. Echo-cardiographic or cinefluoroscopic findings enhanced diagnosis mainly in advanced stages of the disease. Despite medical therapy and prompt reoperation in most cases, mortality remains high: 66%, 80% in the early group, 50% in the late group; the prognosis was definitely improved, however, by surgical treatment.