INTRODUCTION: Secondary lack of iron in patients on hemodyalisis is the main cause of inadequate answer on therapy of recombinant human erythropoietin (rHuEPO). Therefore, it is very important to follow the status of iron in these patients. OBJECTIVES: The objectives of our study were to define the value of hemoglobin content in reticulocytes as predictor of functional iron deficiency on hemodialyzed treated patients with erythropoietin (rHuEPO) then evaluate the eficiency of using the value of hemoglobin content in reticulocytes in administration of iron HD (Patients on hemodialyzed ). PATIENTS AND METHODS: It is a prospective study which included 53 patients treated on chronical hemodialysis and continuing hospital peritoneal dialysis (CAPD), all patients were given additional iron therapy intravenously in order to keep the level of ferritin between 300 microg/l and 500 microg/ and transferrin saturation over 20%. The patients were both male and female randomly chosen. The following parameters conected to iron deficiency were compared in this study. The study was taken in the period from august to december 2008 at University Clinical Centar Tuzla. RESULTS AND DISCUSSION: The study included patients from chronical HD programme in therapy with rhEPO, iron intravenously, than patients on CAPD also in therapy with rh EPO and intravenously iron and patients on chronical HD with intravenously iron without rh EPO therapy. There wasn't any significant difference between numbers of male and female patients that were examined and in control group. In this study the following parameters conected to iron deficiency were compared. There wasn't any significant difference in values of seruum ferritin, Ret-he and hemoglobin between the examined and control group. Still, it's clear that members of the examined group had higher values of these parameters comparing to the control group. If we would use criterias like the saturation transferrin and the level of ferritin as referent standard we would have 26/53 (49.1%) patients with iron deficiency in the whole sample. CONCLUSION: Following chematological and biochemic parameters in examined patients on HD are giving us essential information for planing and leading an adequate erythropoietin therapy. For the maximum effect of rhEPO therapy, an adequate compensation of iron is necessary.