The evolution of serum ferritin levels in Ill chronic-hemodialysis patients is prospectively studied. Patients were classified in two groups according to the presence or absence of’hemochromatosis antigens’ (HLA A3, B7 or B14) in their HLA typing. Levels of serum ferritin were similar in both groups before they started dialysis and during the first year. On the contrary, in the second and third hemodialysis years serum ferritin was higher in the group carrying ‘hemochromatosis antigens’. These differences were observed in patients treated with parenteral iron either in the form of transfusions or as intravenous dextran-iron but not in patients receiving oral iron. We conclude that the risk of developing iron overload is greater in hemodialysis patients with HLA A3, B7 or B14. Nevertheless, this potential risk can be minimized with a restrictive policy on the use of parenteral iron (transfusions, intravenous dextran-iron).