The Fontan procedure was physiological correction which was initially applied to tricuspid atresia. We had used the modified Fontan operation in 8 cases at National Medical Center, Seoul, from Aug. 1984 to Oct. 1986. Age range was 20 months to 15 years [mean: 9 years] and male: female ratio was 5:3. 5 patients had tricuspid atresia [lb: 2 cases, Ic: 1 case, lib: 1 case, & llc: 1 case], 2 Patients had univentricular heart of left ventricular type, and one patient had transposition of great arteries with complete endocardial cushion defect. The operative principle was direct anastomosis between right atrium and pulmonary artery, whether main pulmonary artery or right pulmonary artery without any conduits. Postoperatively all patients needed high central venous pressure for adequate hemodynamic status in both survival [20-24 CmH2O] and mortality groups [20-24 CmH2O]. The fatal complications were as follows: empyema with bronchopleural fistula [1 case], bleeding tendency & brain damage [1 case], low cardiac output syndrome & acute renal failure [2 cases], and right to left shunt of unknown origin [1 case]. There were 5 hospital deaths; 3 of 5 tricuspid atresia patients, 1 of 2 univentricular heart patients, and 1 of 1 transposition of great arteries with complete endocar4ial cushion defect patient. The overall mortality was 62.5%. 3 survivors were nearly compatible with Choussat & Fontan criteria. Thus appropriate patient selection and experienced surgical technique were required for good results.