Despite IgG prophylaxis, occasional cases of Rh isoimmunization occur and will probably continue to do so for at least a decade. Can intrauterine transfusions help? In the author's hands, 76% of all nonhydropic fetuses treated over a 13-year period have survived (85% in recent years), and the mortality risk per transfusion has been 3.6% (2.2% recently). The method behind these results is detailed.