It has been 10 years since epoetin-alpha was approved by the federal Food and Drug Administration for use in end-stage renal disease patients. Over this period of time, clinical studies have shown a relationship between the correction of anemia and improved cardiac function, cognitive ability, sexual function, and exercise capacity. Recent large epidemiological studies have shown that mortality and morbidity are reduced when the hematocrit (Hct) level is in the range 33% to 36%, and the National Kidney Foundation's Dialysis Outcomes Quality Initiative (NKF-DOQI) guidelines recommend a target Hct of 33% to 36% to enhance patient outcomes. The most recent mortality studies show that Hcts less than 30% (or hemoglobins less than 110 gm/L) are associated with an 18% to 40% increased associated risk of death and hospitalizations. Higher Hcts in the 33% to 36% range appear to be associated with a 7% reduced risk of death and hospitalizations compared with patients with Hcts of 30% to less than 33%. Patients with sustained Hcts of 33% to 36% over 1 year appear to have the best outcome compared with patients with Hcts that fall. These studies suggest that the factors that may influence patients' ability to move into higher Hct ranges need to be determined to enhance patient outcomes. Dramatic improvement in hemodialysis patient Hct levels has occurred since 1989. Mortality and hospitalization studies support the NKF-DOQI target Hct range of 33% to 36% as providing the best associated outcomes.