The percentage of hypochromic erythrocytes (%HYPO) and the reticulocyte hemoglobin content (CHr) have been used for the diagnosis of iron deficiency (ID). However, we found a discrepancy between %HYPO and CHr values in some hemodialysis patients. Hemodialysis patients receiving recombinant human erythropoietin (rHuEPO) with ID were defined as patients with a %HYPO value exceeding 5%. Five ID patients with a high CHr (group A) and 3 ID patients with a low CHr (group B) received 120 mg/week iron intravenously for 8 to 12 weeks. Changes in %HYPO, CHr, percentage of macrocytic erythrocytes (%MACRO), absolute reticulocyte count, immature reticulocyte fraction, and soluble transferrin receptor level were investigated over a 20-week period. CHrs were measured with 2 hematology analyzers: the Bayer HealthCare Technicon H*3 and the ADVIA 120. Patients in group A showed a significantly greater mean %MACRO (P < .01) and a lower mean red blood cell number (P < .05) than patients in group B. Even the mean CHr at baseline in group A was significantly higher than the mean CHr in the healthy subjects (P < .01), and hemoglobin levels increased in association with the reduction in rHuEPO dose following iron administration (P < .01). We found a group with high CHr, %HYPO, and %MACRO values among hemodialysis patients. Iron administration enables the rHuEPO dose to be reduced.