We report a case of massive chronic foetomaternal hemorrhage. The labor course was uncomplicated. The newborn presented with pallor. tachypnea, and moderate hepatosplenomegaly. The initial hemoglobin was 6.5 g/dl. The Kleihauer-Betke stain on a maternal blood sample was 12%, which is equivalent to 540 ml of fetal blood in the maternal circulation. A clot in the umbilical vein was demonstrated sonographically. The possible association of foetomaternal hemorrhage with umbilical vein thrombosis is discussed.