Congenital cystic adenomatoid malformation is one of a rare congenital malformation usually unilateal in volving a part of lobe or a whole lobe of the fetal lung, charerterized by excessive growing of terminal respiratory element. We made a prenatal diagnosis in a case of congenital cystic adenomdtoid malformation with dif fuse bilateral involvement, Stocker Type III which is associated with fetal hydrops.