Isolation of the left innominate artery from the right aortic arch is a rare anomaly. Herein, we present an even rarer case of incomplete isolation of the proximal left innominate artery with the right aortic arch in a 3-month-old female infant with a double-outlet right ventricle and pulmonary stenosis. Surgical repair at 6 months of age was successful, leading to the restoration of adequate flow in the left arm.