Between October 1979 and June 1986, modified Fontan procedures have been performed on 22 patients by the Department of Thoracic and Cardiovascular Surgery, Yonsei University College of Medicine. Twelve patients had tricuspid atresia; one, congenital tricuspid stenosis; five, single ventricle; two, I-transposition of the great vessels; one, double outlet right ventricle, and one, pulmonary atresia with an intact ventricular septum. There were 9 operative deaths [mortality; 40.9%]. The causes of death were right heart failure in six patients and pulmonary venous hypertension in one who misdiagnosed preoperatively. Another two were deceased due to sepsis and cerebrovascular accident at postoperative 35 and 34 days in each. There were 7 patients below 4 years of age at the time of operation and among them 4 patients were deceased. The operative death was not related with patients` age above and below 4[p=0.211]. The relation between operative death of tricuspid anomaly and another cardiac malformations was statistically significant [p=0.048]. The operative procedures with or without valved conduit [woven dacron] was related significantly [p=0.043] in the case of the 21 of the patients, but the modified Fontan operation with a valved conduit was performed early stage in this series. Since 1982, we operated on 4 patients, doing a right atrium-right ventricle anastomosis without a conduit. All survived and remained in functional class I [NYHA]. The right atrial pressure [RAP] was elevated significantly after operation [mean 9.9$pm$4.8 ~16.9$pm$3.6 mmHg, p<0.001]. The relation between the postoperative RAP of the survival group [16.5$pm$4.3 mmHg] and the group who died [17.4$pm$2.2 mmHg] was statistically significant [p=0.047]. There was no relation between any operative death and any previous palliation. All patients were followed for 4 months to 80 months, except one who was lost to follow up at 2 months following surgery [mean 11.4 months, 238 patient. months]. All were in functional class I with 5 on medications and 7 not. One was reoperated at 70 months following the first operation, due to conduit stenosis. She was moderately impaired in activity, with hepatomegaly after the second operation.