Univentricular heart is a rare congenital cardiac anomaly in which the atrial chambers are connected to only one ventricular chamber and it consists of a diverse group of cardiac malformation characterized by both AV valves or a common AV valve opening into the same ventricle, or the presence of only a solitary AV valve. In spite of recent development in cardiac surgery, corrective operations for univentricular heart still have high mortality and complication rate. Twenty eight patients underwent corrective operation for univentricular heart at Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital from February 1979 to July 1986. Of the 28 patients, 7 patients were operated on by ventricular septation and 21 patients by modified Fontan operation. Of the 28 patients, 19 patients were male and 9 patients female and ages ranged from 5 months to 18 years old with the average age of 7.3 years. There were 2 mortalities in 7 patients operated on by septation with the mortality rate of 28.6% and 5 complications, 3 complete AV block, 1 low cardiac output and 1 arrhythmia. All survived patients are being followed up without specific problem till now. There were 10 mortalities in 21 patients operated on by modified Fontan operation with the mortality rate of 47.6% and 10 complications, 2 low cardiac output, 2 respiratory failure necessitating tracheostomy, 2 persistent cyanosis, 2 arrhythmia, 1 missing of left AV valve in situs inversus patient due to misdiagnosis and one rupture of closed right AV valve. Incremental risk factors for operative mortality are young age less than 5 years old, anomalous pulmonary and systemic venous drainage and atrial septation procedure. In 11 survived patients, 9 patients show good follow-up results but one patient complains of persistent cyanosis and another one patient is suffered from CHF. In our series, results of corrective operation for univentricular heart shows continuing improvement but still high mortality and complication rate. So there must be continuing improvement in surgical result by selection of patient, by adequate decision making for timing and method of operation and by improving operative methods.