The debilitating symptoms of the anemia associated with end-stage renal disease (ESRD) may have a profound effect on patients' quality of life. Until now it has been difficult to differentiate symptoms caused by the anemia from those caused by uncleared uremic toxins and other concomitant diseases. Treatment with recombinant human erythropoietin (EPOGEN, AMGEN Inc, Thousand Oaks, CA) largely eliminates the anemia associated with ESRD; it therefore offers a means of improving patients' quality of life while also clarifying the possible causes of the various symptoms. However, because quality of life involves many factors, such as self-concept, interpersonal relations, and work identity, an improvement in the anemia will have a varying impact on different individuals.