The treatment of hydrops fetalis, a critical state of extravascular fluid overload in the newborn, poses a great medical challenge. The aim of this study was to investigate the use of continuous arteriovenous hemofiltration (CAVH) in the treatment of five critically ill newborns with hydrops fetalis of different etiology. All patients had anasarca, oliguria not responsive to diuretics, were on mechanical ventilation, and were treated with inotropic drugs and sedation. The duration of treatment ranged from 42 to 114 h and all patients, except one who died from congenital heart disease, achieved the clinical goals of weight loss and restoration of diuresis. Regular clinical and neurological follow-up to the age of 2 years was normal for the four surviving patients. In conclusion, CAVH appears to be a safe treatment of fluid overload in newborns with hydrops fetalis.