Ventricular septal rupture(VSR) after acute myocardial infarction(AMI) is a rare and serious complication that is associated with extremely high mortality. Delayed VSR is particularly uncommon and is difficult to diagnose and treat. A 68-year-old man presented with dyspnea on effort. Coronary angiography revealed subtotal occlusion of the right coronary artery(RCA) with collateral circulation to the chronically and totally occluded left anterior descending artery (LAD). Elective stenting of the RCA was successfully performed for a recent MI of the RCA, while percutaneous coronary intervention(PCI) in the LAD ended in failure. At 21 days after the 1st PCI, the patient developed acute heart failure with new pansystolic murmur. Cardiac catheterization showed a left to right ventricular shunting without new coronary artery lesions. Fortunately, the hemodynamic status was stable, and we could perform elective surgical repair by right atrial approach. Simultaneously, a left internal thoracic artery bypass to the LAD was performed. The postoperative course was uneventful. The patient is currently doing well at 5 years after the operation.