OBJECTIVE: Prenatal diagnosis of congenital heart disease(CHD) has been made by fetal echocardiography and its clinical impact on the outcome of affected cases has been reported. METHODS: A multicenter retrospective study was performed by our study group for the fetal diagnosis of CHD, confirmed postnatally or at second study and/or at autopsy and/or follow up. 274 cases out of 8 centers operating fetal echocardiography in high risk pregnancies were analyzed and their outcome was analyzed according to the presence of associated factors and with respect to the types of the CHD. RESULTS: There were 179 cases of significant CHD, 72 cases of miscellaneous CHD, 23 cases of fetal arrhythmias. Significant CHD consisted of 42 cases of ventricular septal defect(VSD), 17 cases of heterotaxia induding asplenia and polysplenia, 15 cases of complete atrioventricular septal defect(AVSD), 15 cases of coarctation of aorta, 14 cases of hypoplastic left heart syndrome(HLHS), 13 cases of tetralogy of Fallot(TOF), 11 cases of double outlet right ventricle(DORV). These 6 frequent CHDs consisted of 70.9% of significant CHD. The gestational age of the fetuses at diagnosis was 20-41 weeks(83 cases from 5 hospitals: Kangnam and Bundang CHA hospital, Ewha women's university hospital and Samsung medical center). 28.9%(24 out of 83 cases with known gestational age at diagnosis) had been diagnosed before 25 weeks of pregnancy. The most common indication of fetal echocardiography was abnormal obstetric ultrasound findings. Associated extracardiac and chromosomal anomaly was 27.9% and 11.7% respectively. The rate of termination of pregnancy(TOP)/significant CHD was 34.1%. Perinatal mortality was 39.7% induding 61 TOP, 5 fetal death in utero(FDIU), 4 neonatal death and 1 neonatal operative death. The most common factors of TOP were extracardiac and chromosomal anomaly. Five cases of d-transposition of great arteries with intact ventricular septum had been diagnosed prenatally at 3 hospitals, all of them had planned delivery and all survived arterial switch operation in the neonatal period. CONCLUSION: This study represents the impact of fetal echocardiograhpy on the outcome of CHD in Seoul and part of Kyung-Gi area in 1998. The data suggested that significant CHDs could be diagnosed accurately in most hospital But the prenatal detection rates of CHD were relatively low in several hospitil compared to the number of livebirth, probably due to inaccurate prenatal ultrasound screening.