We investigated the effect of subcutaneous anti-D IgG as platelet enhancing therapy in children with idiopathic thrombocytopenic purpura (ITP). Twenty-three children were treated with subcutaneous anti-D 50 microg/kg. The median platelet count increased from 7 x 10(9) to 31 x 10(9)/L on day 3 (P < 0.01). The median decline in hemoglobin was 1.3 g/dl. Two children experienced minor fever and chills within 24 hr of treatment. Pain at the injection site was common but self-limiting with no effect on activity level. These results suggest subcutaneous anti-D IgG 50 microg/kg as an effective and well-tolerated treatment option in childhood ITP.