Iron overload is a constant and the more important complication in thalassemia. Serum ferritin concentration accurately reflects body iron stores. A total of 245 thalassemic patients aged 12-55 years were examined, 71 having Hb H disease and 174 beta-thalassemia/Hb E disease. The patients received minimal or no blood transfusions. 73 patients with beta-thalassemia/Hb E were studied 1-28 years after splenectomy. The serum ferritin levels in both Hb H and beta-thalassemia/Hb E patients were higher than normal. They were higher in beta-thalassemia/Hb E than Hb H disease. Most striking was the significantly higher serum ferritin levels in splenectomized patients with beta-thalassemia/Hb E disease than in the nonsplenectomized ones. The observation is compatible with previous observations that splenectomy in thalassemia is associated with increased iron deposition and increased transferrin iron saturation. The further increase in iron overload after splenectomy in thalassemia should be borne in considering removal of this organ.