In the era before reperfusion therapy, ventricular septal rupture complicated 1approximate3% of acute myocardial infarctions (AMI) usually 3-5 days after onset. Studies have reported a positive correlation between the incidence of septal perforation and total occlusion of the coronary arteries. A 70-year old female patient was referred to the emergency room with the diagnosis of acute anterior myocardial infarction (MI) and recent cerebral infarction. The coronary angiogram showed a 90% stenosis at the mid-portion of the left anterior descending artery (LAD), and the lesion was successfully treated by percutaneous coronary intervention (PCI) with stent implantation. After PCI, the anterior wall motion improved on the follow-up echocardiogram. However, on the 20th hospital day, the patient condition deteriorated suddenly with pulmonary congestion. The echocardiography revealed a 1.3 cm ventricular septal defect at the apical septum with a left-to-right shunt. We report this rare case of delayed septal rupture in a patient with patent LAD after PCI and recovery of wall motion.