A total of 106 operations have been performed in the Cleveland Clinic Hospital for insertion of Starr-Edwards1 aortic and mitral valve prostheses. This report briefly presents the reasons we have selected this ball-valve prosthesis in the treatment of acquired valvular heart disease, and the details of our clinical experience to date. Operations for acquired valvular heart disease employing extracorporeal circulation were first performed at the Cleveland Clinic Hospital in 1956. The anticipation of operating upon valves under direct vision proved to be a great stimulus. Hence, the first attempts to correct mitral and aortic insufficiency by plastic procedures were undertaken with confidence and enthusiasm. On occasion the initial results were more than satisfactory, and this success prompted several reports2,3 that advocated various types of plastic procedures for incompetent valves. A variety of procedures, including decortication, simple commissurotomy, annuloplasty, and valvuloplasty were undertaken for the full range of acquired