The development of fetal hydrops in conjunction with intrathoracic pathology has been described, but rarely in association with pulmonary sequestration. The current report presents three cases of antenatally identified nonimmune hydrops fetalis, seen in association with pulmonary sequestrations. In one case, a left-sided chest mass also was defined. One infant was born by emergency cesarean section because of fetal distress at 34 weeks' gestation; the other two were delivered vaginally at 30 and 36 weeks. Two of the newborns were severely hydropic and required aggressive cardiorespiratory resuscitation that included bilateral chest tubes for massive pleural effusions. The third infant was stable at the time of birth, but thereafter respiratory distress developed, and intubation and ventilation became necessary. Two of the infants had a left-chest mass and the other had a right-sided mass, all identified by chest x-ray. Subsequent ultrasonography showed a chest mass and an identifiable systemic feeding artery in two of the patients. For the third, a specific diagnosis was not made before surgery. After resolution of hydrops, all three infants had successful removal of their intrathoracic pulmonary sequestrations. Two of these were found to be extralobar, and the other was an intralobar sequestration of the left lower lobe.