In a series of 833 operations with implantation of 1011 prosthetic valves there were 64 reoperations on 44 patients, an incidence of 7.6%. In almost 50% of the cases, reoperation was motivated by desinsertion. The incidence of desinsertions increased with the number of reoperations. In 40% of the cases, desinsertion was caused by endocarditis. The degeneration of bioprosthetic valves was rapid in children. Thromboembolic accidents occurred in patients with mitral valve mechanical prosthesis. Peri-operative mortality due to left ventricular dysfunction was 9%. Mortality rate was high after reoperation for endocarditis on a desinserted prosthetic valve. Surveillance and prevention of bacterial endocarditis remain of paramount importance.