Papillary muscle rupture associated with acute myocardial infarction (AMI) is well known, but it's incidence is rare. We report a case of mitral valve repair with artificial chordae for partial papillary muscle rupture after AMI. A 75-year-old man underwent percutaneous coronary intervention(PCI) for right coronary artery because of AMI about 2 months ago at another hospital, and suffered from dyspnea 1 week after PCI. He had emergency admission to our hospital for cardiac failure. Echo-cardiogram revealed severe mitral regurgitation due to posterior papillary muscle rupture. We performed mitral valve repair with neochorda implantation to left ventricular wall of papillary muscle rupture site and ring annuloplasty. Mitral regurgitation was well controlled on postoperative echo-cardiogram. He was discharged at 25th postoperative day with no morbidity.