A prospective study to assess the immune functions in splenectomized thalassaemic children. Children were those registered in the Thalassemia major. There were 10 splenectomized children (Group 1), 10 non-splenectomized children and 6 age-matched control (Group 3). All children were shown to be HIV seronegative. The mean concentrations of serum IgG and IgA were higher in Group 1 as compared to Groups 2 and 3 but the differences were not statistically significant. Nitroblue tetrazolium (NBT) dye reduction by stimulated polymorphonuclear leukocytes was normal in both study and control groups and the differences were not statistically significant. However, NBT reduction in the unstimulated state was much higher in Group 2 as compared to Groups 1 and 3. Phytohaemagglutinin induced mitogen proliferation was normal in all 3 groups. Children in Group 1 not only had a significantly higher absolute lymphocyte count but also had a lower CD4/CD8 ratio as compared to Groups 2 and 3. Splenectomy does appear to alter the immune status of thalassemic children but the exact mechanism by which this occurrence is not clear.