A 3-year old female who underwent modified Fontan operation for the double outlet right ventricle with hypoplastic left ventricle at the age of 15 month was admitted with hemoptysis, which was developed 4 days prior to visit. Cardiac catheterization revealed that multiple collaterals from descending thoracic aorta supplied the right lung and drained to the right pulmonary artery. Chest magnetic resonance imaging [MRI showed that the right lung was consolidated by the secondary long-term pulmonary congestion. We decided to perform pneumonectomy because the consolidated right lung and the back-flow from the right pulmonary aretry would worsen the present hemodynamic state of patient. Post-operative course was uneventful, and she could be discharged with good general conditions.