This study was purposed to investigate the effect of gemcitabine (GEM) on granulocyte colony-stimulating factor receptor (G-CSFR) and bcr/abl mRNA in patients with chronic myeloid leukemia (CML). 23 cases of CML in chronic phase, 8 cases of CML in blastic phase and 10 cases of non-hematologic diseases with normal bone marrow were enrolled in this study. The bone marrow from all these cases was collected and divided into 2 group: GEM group (bone marrow cells of CML patients and normal bone marrow cells were cultured with 10 µg/ml GEM for 48 hours) and control group (above-mentioned bone marrow cells were cultured without GEM for 48 hours). The expression of G-CSFR was detected by flow cytometry, the expression of bcr/abl mRNA was assayed by RT-PCR. The results showed that the G-CSFR expression rates of bone marrow in CML chronic phase and blastic phase as well as normal bone marrow in GEM group were (50.72±8.57)%, (36.32±4.25)% and (59.42±7.62)% respectively, while the G-CSFR expression rates of above-mentioned bone marrow in control group were (45.42±6.52)%, (30.58±5.68)% and (58.56±5.54)% respectively. The comparison of G-CSFR expression rates between bone marrow of CML and normal bone marrow, between bone marrow of chronic phase and blastic phase and between bone marrow of GEM group and control group all demonstrated significant difference (p0.05). The negative correlation of G-CSFR expression rate with bcr/abl mRNA expression level was observed in GEM and control groups as well as in CML chronic phase and blastic phase of GEM group (r=-0.747, p<0.01; r=-0.803, p<0.01 respectively). It is concluded that the GEM can in vitro enhance the expression rate of bone marrow G-CSFR in CML patients at chronic or blastic phases, but no significant effect on expression of bcr/abl mRNA. The negative correlation of G-CSFR expression rate with bcr/abl mRNA expression level exists in CML patients at chronic or blastic phases.