Abstract： Objective To detect the abnormalities of differentiation and expression of membrane hemopoietic cytokine receptors on CD34 + bone marrow cells in patients with myelodysplastic syndromes (MDS). Methods Forty-five newly diagnosed MDS cases from July 2008 to March 2010 in our hospitaland 30 normal controls were enrolled. There were 17 low-risk and 28 high-risk patients. The CD34 + CD38 +and CD34 + CD38- bone marrow cells and the expressions of stem cell factor receptor (SCF-R),erythropoietin receptor (EpoR), granulocyte colony-stimulating factor receptors (G-CSFR) and thrombopoietin receptor (TpoR) on those cells were measured by flow cytometry. Results The mean percentage of CD34+ in karyocyte of MDS cases in high-risk patients [0. 53% (0. 10% - 1.68% )] was significantly higher than that of control group [0. 13% ( 0. 08% - 0. 32% ), P ＜ 0. 01] . The mean percentages of CD34 + CD38 + cells were significantly lower in low and high-risk groups (86. 3% ± 8.5% and 82. 6% ± 11.1% ) than those in control group (92. 3% ± 3.4% ). And the percentage of CD34+ CD38-cells was significantly higher in either low-risk or high-risk group ( 13.7% ±8. 5% and 17.4% ± 11.0% )than that in control group (7.7% ± 3.4%, both P ＜ 0. 05 ). In control group, the mean percentage of antigen expression of EpoR was significantly lower in CD34 + CD38 + cells than that in CD34 + CD38 - cells ( 18.7% ± 18. 3% vs 63. 6% ±20. 0%, P ＜0. 01 ). The expressions of SCF-R, G-CSFR and TpoR were not significantly different between two cell populations. The expressions of EpoR on CD34 + CD38 + cells of low and high-risk MDS groups [9.0% ( 1.4% - 12. 7% ), 5. 2% ( 1.1% - 14. 1% )] were significantly lower than those of control group [9. 6% (5.1% - 30. 1% ), both P ＜ 0. 05]. The expressions of G-CSFR on CD34+CD38+ cells of low and high-risk MDS groups (29.8% ± 19. 1%, 28.7% ± 21.1%) were significantly lower than those of control group (44.4% ± 23.4%, both P ＜ 0. 05 ). The quantities of EpoR on CD34 + CD38 - cells of low and high-risk MDS groups ( 42. 2% ± 21.9%, 25.7% ± 15. 6% ) were significantly lower than those of control group ( 63. 6% ± 20. 0%, both P ＜ 0. 01 ). The expressions of TpoR on CD34+ CD38- cells of low and high-risk MDS groups (5.4% ± 4.7%, 4.1% ± 4.0%) were significantly lower than those of control group ( 10. 1% ± 8. 3%, both P ＜ 0. 05 ). The incidence of cytopenia with low expression rates of hemopoietic cytokine receptors on CD34 + cells was higher than that of MDS with high expression rates. Conclusion The abnormalities of differentiation and membrane hemopoietic cytokine receptors expression of CD34 + bone marrow cells in MDS are associated with MDS cytopenia and may be useful for the diagnosis of MDS.