During a 6-year period, from January1990 to December 1995, 101 neonates with congenital anomalies were admitted to the division of Pediatric Surgery of Y oungdong Severance Hospital. All of them had prenatal screening more than once with ultrasound. Fifty eight of them had prenatally detectable anomalies by ultrasonography. However abnormalities were prenatally detected in 24 neonates( 41 %). The detection rate was 70% in patientws who had the prenatal screening at our hospital, whereas, the rate was 24% when it was performed at other medical facilities. Duodenal and jejunoileal atresia showed the highest detection rate(86%) followed by abdominal mass. Esophageal atresia was suggested by maternal polyhydramnios in 3 patients(25%). Only one patient with diaphragmatic hernia ( 1.75%) was prenatally detected and none with gastroschisis. The mean interval from birth to operation was 32 hours in the prenatally detected patients and 50 hours in the nondetected. The complication rate and the mortality after emergency operation were 20% and 7% in the detected group, and 58% and 23% in the nondetected, respectively. The average period of the hospitalization was 20 days in the detected group and 39 days in the nondetected. We conclude that the prenatal detection of anomalies is necessary to ensure adequate care for the mothers and the babies with congenital anomalies. This includes early transfer, timing of optimal delivery and operation.