OBJECTIVE: Anemia is a common problem in chronic renal failure. Recent studies have shown that there is a close relationship between fluctuations in hemoglobin values and increased mortality. Therefore, treatment of anemia and providing stable hemoglobin (Hb) levels with erythropoiesis-stimulating agent (ESA) is important in the management of chronic renal failure. Hence, ESA usage and relationship between ESA type and Hb variability were investigated in hemodialysis patients. MATERIAL and METHODS: 130 patients treated at a hemodialysis center were monitored monthly for one year. The mean age was 60±7 years, mean weight was 72±13 kg, and mean dialysis duration was 5 ±2 years (F/M: 64/66). Hb stability was defined as continuous ESA usage at maintenance dosage and Hb levels being at the target level (Hb≥11g/dl) for last 12 months. Hb variability and ESA dose change was accepted as decrease of Hb levels under 11 g/dl during maintenance dosage use and increasing ESA to starting dosage. In our study, annual mean values of monthly prescribed ESA rates, types of ESA and weekly dosages, and changes in ESA dosages due to monthly changes in hemoglobin (Hb) levels were examined. The relation between ESA type and Hb variability was investigated. RESULTS: During a one-year period, the number of patients who did not use ESA (Hb levels always >12 g/dl) was 5 (%3.8) and the number of patients who used ESA for different periods was 125 (%96.2). The mean number of patients using ESA monthly was 71 (57%). 32 (45%) patients used short acting, 31 (44%) used medium acting (darbepoetin) and 8 (11%) used long acting ESA (methoxy polyethylene glycol-epoetin beta). 26 patients (21%) used ESA at the starting dose and 45 (36%) at the maintenance dose. One third of the 71 patients (36.6%) were using ESA at the starting dose and two thirds (63.4%) were on the maintenance dose. Mean weekly short acting ESA dose was 9666±2376 IU in the starting dose group and 5400±1142 IU in the maintenance group. Mean weekly darbepoetin dose was 46.6±10,3 mcg in the starting dose group and 26.4±4,9 mcg in the maintenance group. There were no Hb changes in 33 patients (26.4%) but 92 (73.6%) had Hb variability during one year. During one year, the Hb level dropped under 11 g/dl once in 32 patients (35%), twice in 39 patients (42%), three times in 16 patients (17%) and four times in 5 (6%) patients and the ESA dose was increased to the starting dose. Number of monthly Hb changes was higher in the short acting ESA than the medium and long acting ESA groups. CONCLUSION: Our results revealed that monthly ESA usage rate and weekly ESA dosage were lower than in western countries. During the one year period, there was Hb variability in three in four of the patients and ESA dosages were changed. The number of monthly Hb variability cases was found to be lower in the medium and long acting ESA groups. The most important reason of Hb variability was monthly dose change or discontinuation of ESA, due to the limits in the application of ESA.