We carried out a pilot study on the use of recombinant human erythropoietin (rHuEPO) to accelerate erythropoietic engraftment in paediatric patients undergoing allogeneic BMT. rHuEPO was administered intravenously at a dose of 75 U/kg per day for 30 d after transplant. Erythroid repopulation, evaluated sequentially through the serum transferrin receptor, was faster in 15 patients receiving rHuEPO than in 16 historical controls (P = 0.0003). This faster erythroid engraftment resulted in a reduction in the total number of red blood cell units required to reach transfusion independence (2.7 +/- 1.2 v 4.2 +/- 2.3, P = 0.027). No significant difference in leucocyte or platelet regeneration was observed. These findings indicate that rHuEPO administration can accelerate erythroid recovery after allogeneic BMT and reduce red cell transfusion requirements with no stem-cell competition effect.