The left ventricular wall rupture is not only a rare complication after mitral valve replacement, but also a high mortality disease. We have encountered a case of this complication after removal of the extracorporeal circulation in an octogenarian female after mitral valve replacement with Carpentier-Edwards (25 mm). It could be successfully repaired from outside the heart on the cardiopulmonary bypass without second cardiac arrest. Repair from inside the heart using extracorporeal circulation and cardioplesia is generally recommended because of the accuracy. However, second cardiac arrest might be a risk of postoperative complications in octogenarians. Hence, prevention is the most important. And operative strategy for the repair is also important in these patients.