To assess 6 years' neurologic outcome of a complete cohort of survivors of intrauterine intravascular transfusions.From January 1986 to December 1991, 136 intravascular transfusions were performed in 43 fetuses presenting with signs of severe erythroblastosis. Before the initial transfusion, 11 of 43 fetuses had some degree of hydrops fetalis, and hemoglobin values ranged between 1.5 and 10.7 g/dL. Neurologic outcome of a complete cohort of 35 long-time survivors was assessed for up to 6 years by reviewing the hospital charts and questionnaires sent to the family physicians or pediatricians.Long-time follow-up was available in all survivors with hydrops at initial transfusion (seven of seven) and in 23 of 28 survivors without hydrops. Only one of 35 survivors had mild psychomotoric disabilities up to 1 year of age, but was free of sensorineural problems on further examination. In a second case, delayed speech development was observed. Fetuses presenting with hydrops fetalis before initial transfusion tended to have a higher perinatal mortality and had a significantly higher rate of preterm delivery (P = .03). However, moderate or severe neurologic impairment was never observed, even when severe cases with hydrops fetalis or extremely low hemoglobin levels were included.Treatment of severe fetal erythroblastosis by intrauterine intravascular transfusions is associated with a favorable neurologic long-time outcome.