From January 1978 to December 1988, 71 patients underwent surgical intervention at our institution for prosthetic valve endocarditis with ring abscesses. These procedures involved 59 aortic prostheses and 12 mitral prostheses. No causative agent could be identified in 19 patients (26.7%). The operation was performed during antibiotic therapy in 63 patients and after a planned course of antibiotic therapy in 8 patients. At the aortic level, abscesses were remedied by suturing in 3 cases, by pericardial patches in 34 cases, and by complex procedures in 22 cases (subcoronary valved conduit in 11 cases, supracoronary valved conduit with coronary bypass grafts in 10 cases, apicoaortic valved conduit in 1 case). At the mitral level, ring abscesses were cured in 10 cases by intraatrial implantation of the prosthesis. In one case, the prosthesis was anchored inside the left ventricle; and in one case the valve could be seated on the anulus. The overall operative mortality rate was 17%. Long-term survival was 54% +/- 8% at 6 years. Fifteen (26%) of the survivors needed a third valve replacement (four operative deaths); a complex reconstruction was performed in seven patients. Better detection of ring abscesses and earlier surgical intervention before annular destruction and hemodynamic failure can improve the operative mortality rate for prosthetic valve endocarditis. When it is necessary, complex reconstruction, in spite of a high mortality rate, seems to eradicate the infectious seat, and the outlook for the patient's condition appears good.