The ductus venosus regulates the distribution of oxygen and placental nutrients by restricting the centralization of blood flow in fetal circulation. The ductus venosus is a small vein transmitting oxygen-rich blood from the umbilical vein to the fetal heart.. Increasing numbers of case reports are being published about ductus venosus agenesis with cardiac structural abnormalities, other malformations, chromosomal abnormalities, and stillbirth. Heart failure, hydrops and unexplained polyhydramnios could also be associated with ductus venosus agenesis. In the follow-up of fetuses with ductus venosus agenesis, care must be taken to examine for hydrops and heart failure. The agenesis of ductus venosus is often only found in fetuses by coincidentally. Herein we discuss the prenatal diagnosis of isolated agenesis of the ductus venosus presenting with a dilated inferior vena cava and without any disturbance of fetal hemodynamics and any other malformation. In conclusion a dilated inferior vena cava can be a sign of ductus venosus agenesia.