Pneumocystis carinii pneumonia developed in an 11-year-old girl with chronic granulomatous disease who had normal cellular and humoral immunity. The patient remained febrile during treatment with sulfamethoxazole-trimethoprim and pentamidine but became afebrile when treated with a series of 12 granulocyte transfusions combined with sulfamethoxazole-trimethoprim. In addition to documenting P carinii infection in chronic granulomatous disease our findings suggest that granulocyte transfusions may be of value in the treatment of severe infections in chronic granulomatous disease.