Portal vein anomalies include absence, duplication, and malposition (preduodenal portal vein). Duplication of the portal vein or a preduodenal portal vein are hazards at the time of biliary or duodenal surgery, or liver transplantation. Preduodenal portal vein, which was first reported by knight in 1921, is extremely rare congenital anomaly and may cause duodenal obstruction. Recently, we experienced a case of preduodenal portal vein associated with dextrocardia, situs inversus, and duodenal obstruction in a 3 days old male newborn and report with review of the references.