Isolated origin of the subclavian artery is a congenital anomaly of the aortic arch in which one subclavian artery is attached to the ipsilateral pulmonary artery through ligamentous arteriosus. An isolated right subclavian artery with the left-sided aortic arch is an extremely rare condition. We report on an asymptomatic 2-year-old-girl, who was referred because of an incidental cardiac a murmur. She was diagnosed by echocardiography to have an isolated right subclavian artery connected to the right pulmonary artery in a left aortic arch with a ventricular septal defect. MRI confirmed the findings.