Infective endocarditis is a rare complication of ulcerative colitis. We report on a 22-year-old man, who had been treated of ulcerative colitis for 5 years. He presented with dyspnea on effort. In spite of medical treatment, he developed congestive heart failure. Transthoracic echocardiography showed a large perforation on the anterior leaflet of the mitral valve, and prolapses of the posterior leaflet of the mitral valve with rupture of the chordae. The patient underwent mitral valve repair with an autologous pericardial patch on the anterior leaflet combined with butterfly resection and suture of the posterior leaflet. The postoperative course was uneventful.