Congenital duodenal atresia, which is the most common cause of neonatal intestinal obstruction, occurs rare (incidence: 1/2,700-10,000) but is associated with high neonatal mortality if it is not treated immediately. About two-thirds have combined anomalies, such as congenital heart disease, esophageal atresia, bowel malrotation, renal anomalies and/or vertebral anomalies. About one-third occurs with Down syndrome. Most cases are treated by immediate duodenoduodenostomy, and result in about 5% short term mortality and 86% long term survival. Down syndrome does not influence on the operative morbidity and mortality of duodenal atresia but does carry a high incidence of congenital cardiac anomalies. Targeted ultrasonography for complex fetal anomalies and adequate prenatal counsellings are essential. We report a case of duodenal atresia in Down syndrome fetus, which was diagnosed prenatal ultrasonography and was operated immediate postnatally in Kyungpook national university hospital.