We analyzed the comparative amounts of granulocyte-colony stimulating factor (G-CSFr) and granulocyte macrophage CSF (GM-CSFr) receptors expressed on neutrophils and monocytes in measles patients to investigate the role of these CSFrs in the development of leukopenia including neutropenia and monocytopenia in measles. EDTA-anticoagulated peripheral blood of 19 measles patients, 10 children with other infections showing leukopenia and 16 children with normal complete blood cell counts (CBC)s were analyzed using flow cytometry and QuantiBRITE. The leukocyte (5260 ± 2030/uL vs. 9900 + 2680/uL, p=0.000), neutrophil (2580 ± 960/uL vs. 4250 ± 2750/uL, p=0.024) and the lymphocyte counts of measles patients (1810 ± 1430/uL vs. 4530 ± 3450/uL, p=0.006) were lower than in the normal controls. The neutrophils of measles patients expressed similar amounts of G-CSFr (1858 ± 355) as normal children (1764 ± 477, p=0.564) and leukopenic patients (1773 ± 673, p=0.713), but lower levels of GM-CSFr (535 ± 118) than normal children (957 ± 344, p=0.000) and leukopenic patients (832 ± 294, p=0.002). The monocytes of measles patients expressed similar amounts of G-CSFr (916 ± 336) and GM-CSFr (3718 ± 906) as normal children (1013 ± 391 and 4125 (2645, p > 0.05) but less than leukopenic patients (1454 ± 398 and 5388 ± 806, p > 0.05). The neutrophil and monocyte counts of measles patients did not correlate with the amount of G-CSFr or GM-CSFr expressed on neutrophils or monocytes (p > 0.05), but in the normal children, the monocyte count correlated with the levels of GM-CSFr on monocytes (r=0.951, p=0.049).