Fetal hydrops is an acute disease of fetus, it can happen at any age pregnancies, postnatal consequences of it is very serious with infant mortality rates above 95 percent, fetal hydrops results a wide variety of causes, majority of unexplained. Objectives: preliminary evaluation of characteristics diagnostic ultrasound imaging and determine the cause of fetal hydrops. Materials and methods: retropective study of 251 fetal hydrops who were diagnosed in Prenatal Diagnosis Centre, National Hospital of Obstetrics and Gynecology. Results: the median gestational age was 24,8 + or - 5,7 weeks. The rate of ascites was 82,1 percent, pericardial effusion (48,2 percent), pleural effusion (44,2 percent), subcutaneous edema (47,8 percent), placental edema (39,8 percent). Fetal ultrasound was determined the cause in 29,1 percent cases, the most common cause was malformation of lymphatic system (9,5 percent), congenital heart disease (6 percent), malformation of lung - thorax (4 percent). Conclusion: fetal hydrops usually manifests lately, the most common marker is ascites and these common causes that are determined by fetal ultrasound are malformation of lymphatic system, congenital heart disease, malformation of lung - thorax.