The intravascular volume load that an anemic fetus can tolerate was studied retrospectively in 124 consecutive intravascular transfusions in 35 erythroblastic fetuses. The tolerated volume load correlated well to the estimated fetal weight. Transfusion volume loads above 20 ml/kg of the estimated fetal weight resulted in a lower fetal survival. We recommend an upper transfusion limit at 20 ml/kg corresponding to approximately 20% of the feto-placental blood volume.