Four neonates who had undergone intra-uterine peritoneal blood transfusions for Rhesus disease and hydrops fetalis presented, during the first days of life, with intractable hyperbilirubinemia in spite of multiple exchange transfusions. The hyperbilirubinemia was due to delayed absorption and hemolysis of peritoneal red cells. This unusual complication can be successfully managed with peritoneal lavage which should be performed when the antenatal history is contributive for low absorption of transfused blood.