BACKGROUND Postinfarction rupture of the interventricular septum is usually fatal without surgical intervention. The optimal timing and the most appropriate technique of surgical repair remain unsettled. METHODS The results of surgical closure of postinfarction ventricular septal defect in a consecutive series of patients seen over a 24-year period were reviewed and analyzed. Late follow-up was obtained in all patients who survived the operation. RESULTS Sixty of 76 patients treated surgically exhibited cardiogenic shock, low cardiac output syndrome, or both at the time of operation. A plan of early operative intervention was followed in these unstable patients, with 60% of them undergoing repair within 24 hours of septal rupture. For the entire series of patients, the hospital mortality rate was 40.8%; survival was 41.5% at 5 years and 25.6% at 10 years postoperatively. CONCLUSIONS Significant trends observed during the period of study were a more aggressive stance regarding surgical intervention in all patients who presented with hemodynamic instability and improved survival in those patients who presented with septal rupture complicating an inferior myocardial infarction.