This study determined the long-term outcome for patients after myocardial infarction (MI) due to Kawasaki disease (KD). Retrospective analysis was performed for 60 patients who had experienced MI between 1976 and 2007. Their ages at the initial MI ranged from 3 months to 33 years (median, 2 years). The maximum follow-up period after the initial MI was 33 years (median, 16 years). Coronary angiography, left ventriculography, and radioisotope myocardial perfusion imaging (MPI) had been performed for 56 patients more than 2 months after MI when all were in stable condition. The survival rate and ventricular tachycardia (VT)-free survival rate were calculated after the initial MI by the Kaplan-Meier method. Both sustained and nonsustained VT were included. Furthermore, the Cox proportional hazards model was used to analyze which factors influenced the post-MI outcome and which influenced the appearance of VT. The 30-year survival rate was 62.7% (95% confidence interval [CI], 44.6-77.9%), and the 25-year VT-free survival rate after MI was 28.5% (95% CI 15.4-46.5%). The postinfarction left ventricular ejection fraction (LVEF) was related to the outcome in this population (hazard ratio 0.86; 95% CI 0.75-0.95; P = 0.002), whereas the development of VT was related to the post-LVEF and to perfusion abnormalities in MPI (P = 0.0002). The 30-year survival rate after MI was poor for the patients with a low LVEF. With aging, the existence of nonviable myocardium in the infarct area can induce fatal ventricular arrhythmia more than 10 years after the original MI.