Iatrogenic aortic regurgitation (AR) after ventricular septal defect (VSD) closure occurs because of the distortion of the aortic valve or leaflet perforation. We presented a case of a 1-month-old child who had iatrogenic AR after VSD closure caused by the rotation of the arterial cannula tip toward the aortic valve during cardiopulmonary bypass. Transesophageal echocardiography (TEE) detected a retrograde jet flow from the arterial cannula to the aortic valve, causing eccentric AR. Our case shows a new differential diagnosis of iatrogenic AR after VSD closure and TEE’s usefulness with color Doppler imaging to identify the direction of the arterial cannula tip.