Although intrauterine fetal transfusion has improved dramatically perinatal outcome in Rh D alloimmunization, in some cases the fetus is affected before transfusion is possible. Immune globulin (IVIG) administration is being increasingly used to successfully treat a variety of immune-mediated diseases, such as pregnancies affected by platelet alloimmunization. Although only a limited number of pregnancies have been reported, favorable outcomes with IVIG treatment of severe Rh disease have been described. We present a case report, review the published experience with IVIG treatment in severe, early-onset anti-D sensitization, and propose that IVIG may have an adjunctive role in the treatment of severe Rh isoimmunization.