Hearing loss is a common finding in patients with end-stage renal failure. Uremic toxins, ototoxins, and axonal uremic neuropathy appear to be likely pathogenic factors. We analyzed whether an improvement in hearing capacity can be achieved with an improvement of anemia by erythropoietin (EPO) administration. Fifty patients on long-term hemodialysis in a single center were examined audiologically by otoscopy, tympanometry, pure tone audiometry, and the short increment sensitivity index. Twenty-five patients were treated with EPO in a dose of 120 U/kg per week over a period of 5 to 8 months, and the remaining 25 patients were not treated with EPO (controls). Both groups were reexamined audiologically after the study period, and the results were compared. In the group treated with EPO, the hemoglobin level increased from 7 +/- 0.9 to 11 +/- 0.8 g/dL, as against the control group, whose hemoglobin increased from 7.1 +/- 0.9 to 8 +/- g/dL. The audiologic tests were repeated at the end of the study period, and a significant improvement of hearing was found in the patients treated with EPO as compared with the control group (p < .001). Our study suggests that improvement of anemia in patients on long-term hemodialysis by administration of EPO is associated with an improvement in hearing capacity in a significant number of patients. Thus, anemia seems to be an important factor responsible for hearing disorders in patients with end-stage renal failure. Studies with larger numbers of patients are required to confirm this observation.