Published reports on the impact of recombinant human erythropoietin (r-HuEpo) on transfusion requirements of patients with chronic renal failure have been limited to small populations and relatively brief follow-up. In this study we reviewed the effects of this drug on 86 patients with well-characterized transfusion requirements, followed for 18 months at seven dialysis centers. The median red blood cell transfusion requirements per patient per year decreased from 14 in 1987 and 1988 to 11 in 1989, when r-HuEpo was licensed in the United States (p <.01) and fell to 2 in 1990 (p <.01). The proportion of patients who became transfusion-independent increased from 34 percent in 1989 to 69 percent in 1990 (p <.001). These data demonstrate that r-HuEpo significantly decreases transfusion requirements of patients with chronic renal disease.