Neutrophil chemotaxis and random migration were evaluated in 21 patients with thalassemia major and 21 healthy controls by a filter technique (Boyden chamber). Chemotactic and random migrations in patient group were found to be defective, which may partially account for the increased susceptibility to infection occasionally observed in these patients. The effects of serum ferritin levels, transferrin saturations that show iron overload, total count of blood transfusions for chronic immunostimulation, desferrioxamine therapy, and splenectomy on these neutrophil functions were examined in thalassemic patients in order to determine whether they are responsible for these defective functions because the mechanism of abnormal neutrophil chemotaxis and random mobility in thalassemic patients is not still clear.