A receptor for murine granulocyte colony-stimulating factor (G-CSF) has been found on the cell surface of mouse myeloid leukemia cell line NFS-60. By large scale culture of NFS-60, The receptor in the membrane fraction of NFS-60 cells were solubilized in an active form with CHAPS, The receptor was obtained by centrifugation at 150 000 g for 90 min, The solubilized receptor was purified nearly to homogeneity by a G-CSF affinity gel. The purified receptor has been identified with the method of ABC-ELISA.