We report the surgical correction of an incomplete atrioventricular septal defect (AVSD) associated with pulmonary stenosis in a 72-year-old woman. She was given a diagnosis of atrial septal defect at the age of 19, but at that time surgery was not indicated. She had an uneventful pregnancy at age 28. She had received medical treatment for congestive heart failure since the age of 67. Four years later, she was admitted to another hospital due to edema of the leg and retention of massive ascites. After careful and precise evaluation, AVSD was diagnosed, associated with bilateral atrioventricular (AV) valve regurgitation, pulmonary stenosis, atrial fibrillation and significant stenosis of the left anterior descending (LAD) coronary artery. She was referred to our hospital for surgery, and intracardiac repair was determined to be necessary after clinical assessment. Prior to surgery, she underwent percutaneous coronary intervention with a bare-metal stent for an LAD lesion. Under antegrade cold blood cardioplegia and mild hypothermia, we performed closure of the ostium primum atrial septal defect using a heterologous pericardial patch with expanded polytetrafluoroethylene strip, and right side atrioventricular (AV) valvuloplasty and pulmonary valvotomy. The postoperative course was uneventful. The patient has been designated NYHA class I for 2 years since surgery, and has had mild regurgitation of both AV valves, but neither have affected her quality of life. Surgical correction should be considered in elderly patients with incomplete AVSD, even in those aged 70 and over.