Azygos continuation of the inferior vena cava is diagnosed in infants in the presence of obstruction to flow in the inferior vena cava due to infrahepatic interruption. Recently we studied in an infant complex congenital heart disease in which there was azygos continuation of the inferior vena cava without infrahepatic interruption or any other obstructive lesion of this vessel. The blood from the lower part of the body drained into the right atrium by two wide patent veins: the inferior vena cava and the azygos system. The angiocardiographic observations of this condition in an infant are reported for the first time to our knowledge, and the embryologic development is briefly reviewed.