The sonographic picture of fetal cyclopia at 33 weeks' gestation consists of a small fetal head, a central cavity replacing the cerebral lateral ventricles, lack of midline structures, absence of hemispheral vascular pattern and hydramnios. In addition, in our case a structure projecting from the fetal face correlated well with the proboscis. This sonographic feature is the clue in differentiating fetal cyclopia from other forms of alobar prosencephaly.