We report a case of a 28-year-old female who underwent an extracardiac Fontan procedure. The subject was diagnosed as an atrioventricular septal defect (Rastelli classification: type C), a double outlet right ventricle, pulmonary artery stenosis, a hypoplasty of left ventricle, total anomalous venous return (Darling: Ib + IIb), and atrial flutter. She underwent a Blalock shunt and an aorto-pulmonary shunt at the ages of 3 and 9 years, respectively. Under a total CPB, an extracardiac total cavo-pulmonary connection (TCPC), using a 26 mm Hemashield graft, was completed. The postoperative course was uneventful. The complicated atrial anatomy and atrial arrhythmia indicated TCPC in this adult patient.