Sickle CELL ANEMIA is frequently complicated by severe infection such as pneumococcal meningitis,1 salmonella osteomyelitis,2 and pneumonia.3 An immunologic basis for this predisposition has not been established. Thurman4 suggested that sickle cell anemia patients responded poorly to typhoid and tularemia vaccines but did not accumulate adequate data for statistical analysis. In contrast no deficiency in the response of such patients to salmonella vaccine was noted in a more recent study.5 Abnormalities in serum immunoglobulin levels have been observed in several diseases complicated by recurrent infection. To determine if such abnormalities occurred in sickle cell anemia, serum immunoglobulin values were investigated in pediatric patients with SS or SA hemoglobin patterns and in adults with SS hemoglobin patterns. Elevations of serum immunoglobulin levels, perhaps due, in part, to infection, were observed in patients with sickle cell anemia. In order to further elucidate these changes, patients with another hemoglobinopathy thalassemia major, were added