Intravenous gammaglobulin was used to treat 12 children with chronic immune thrombocytopenic purpura in order to avoid splenectomy. The average rise in platelet count with initial treatment was 226,000/microliters. Currently, one patient is in remission, four patients maintain platelet counts greater than 40,000/microliters without treatment, four patients maintain platelet counts greater than 40,000/microliters with single maintenance infusions of IV IgG at four- or 10-week intervals; three patients did not respond to treatment. In nine of 12 patients, splenectomy was avoided or at least postponed. In responding patients, we were able to discontinue immunosuppressive medication. Platelet count rises with initial IV IgG therapy were correlated with both platelet antibody levels and with a better long-term outcome. Toxicity was minimal.