Background:Ventricular septal defect (VSD) after myocardial infarction (MI) is a rare but fatal complication. We report patients’ characteristics and operative outcomes after surgical repair of post-MI VSD using a national database of Japan.Methods and Results:This was a retrospective review of the Japan Adult Cardiovascular Surgery Database (JCVSD) to identify adults (age ≥18 years) who underwent surgical repair of post-MI VSD between 2008 and 2014. The primary outcome was operative death. We identified 1,397 patients (671 male 48%, 74.1±9.3 years old) undergoing surgical repair of post-MI VSD among 288,736 patients undergoing cardiac surgery enrolled in the JCVSD during the same period. Of these, 1,075 (77.0%) were supported preoperatively with an intra-aortic balloon pump. Surgical status was urgent in 391 (28.0%) and emergency/salvage in 731 (52.3%). Concomitant coronary artery bypass grafting was performed in 475 (34.0%). Overall 30-day and operative mortalities were 24.3% and 33.0%, respectively. Operative mortality varied according to surgical status: 15.6% in elective, 30.9% in urgent, and 40.6% in emergency/salvage cases. Multivariable analysis identified advanced age and emergency/salvage status as being strongly associated with increased odds of operative death.Conclusions:Post-MI VSD remains a devastating complication in Japan as well as in the USA and Europe.