A reoperation to upsize the conduit placed at infancy for the repair of an anomalous origin of the right pulmonary artery (AORPA) was successfully performed in an 8-year-old girl because of an elevated right ventricular pressure and a reduced right pulmonary blood flow. Although primary direct anastomosis is essential for AORPA, one should not hesitate to perform a conduit repair (interposition with a tube prosthesis) on an infant with AORPA whose right pulmonary artery is distant from the main pulmonary artery, because a reoperation can safely be performed even in cases where the conduit is relatively narrow as the patient grows. This is the first report of a reoperation, including a complete replacement of the conduit, after an initial conduit repair for AORPA.