Kawasaki disease (KD) is an acute vasculitis involving all blood vessels with frequent cardiovascular complications. We describe a 28-year-old patient with childhood KD having coronary complications at the age of 17 now presenting with sustained atrial tachycardia. Electrophysiological study and catheter ablation were performed. Electrophysiological study revealed a left atrial (LA) tachycardia (230 ms cycle length) with 2:1 atrioventricular node conduction. The mechanism for the arrhythmia was re-entry around the mitral annulus associated with the low-voltage scar area anterolateral to the annulus and juxtaproximal to the coronary artery calcification seen in fluoroscopy. We describe a patient with childhood KD presenting with LA re-entrant tachycardia associated with the atrial scar. The arrhythmia was successfully treated using radiofrequency catheter ablation.