A case of infectious endocarditis was surgically treated by mitral valve replacement. The patient had previously undergone presternal subcutaneous colonic interposition as reconstruction surgery due to esophageal and gastric cancer. This artificial esophagus prevented the central sternotomy that is necessary for cardiac surgery. In cases where sternotomy is difficult, anterolateral right intercostal thoracotomy is useful. Arterial cannulation was performed via the femoral artery; cannulations for venous drainage were performed in the femoral vein for the inferior vena cava and in the right jugular vein for the superior vena cava in order to establish cardiopulmonary bypass circulation. Under the condition of ventricular fibrillation and a body temperature of 25°C, the mitral valve that had been destroyed by infection was resected by exposure of the left atrium on its right side. An artificial Saint Jude Medical mechanical valve, 29mm in diameter, was implanted. The thorax was insufflated with carbon dioxide gas to prevent air embolization. An aortic vent tube was used for air drainage from the cardiac output. Although a seizure occurred once after the operation, the post-operative course was very stable; currently, the patient (NYHA I) is in very good condition with no recurrence of the cancer.