To evaluate the dynamic changes of erythropoietin (EPO) and its significance following ABO-incompatible allogeneic hematopoietic stem cell transplantation (allo-HSCT), sequential changes in serum EPO levels were measured by enzyme linked immunosorbent assay (ELISA) in 11 patients receiving allo-HSCT from ABO-incompatible donors. The results showed that the mean EPO level was markedly elevated and reached to its highest level at 0 day-2 week after allo-HSCT (233.73 +/- 81.95 mU/ml and 226.07 +/- 113.87 mU/ml respectively, P >0.05). Although the EPO levels were significantly lower at 1 month (128.49 +/- 108.92 mU/ml, P <0.05) and after the reversion of blood type (73.07 +/- 68.85 mU/ml, P <0.05), they were still elevated up to 2 months after allo-HSCT. The EPO levels always had significant positive correlation with the RBC transfusions. At 0 day and 4 week after allo-HSCT, the EPO levels had significant negative correlation with the Hb levels; at 6 and 8 week after allo-HSCT, the EPO levels had no relation with the Hb levels, they had significant positive correlation with the time of erythrocyte recovery and anti-A isoagglutinin titers at the same time. It is concluded that serum erythropoietin levels continuously increasing following ABO-incompatible allogeneic allo-HSCT suggest that exogenous recombinant human erythropoietin treatment for anemia may not be beneficial.