Severe congenital neutropenia (SCN) is a rare disorder characterized by a maturation arrest of myeloid progenitor cells in the bone marrow and severe reduction in the amount of circulating neutrophils. Loss-of-function mutations in the CSF3R (the gene encoding the granulocyte colony-stimulating factor (G-CSF) receptor) have been reported in a handful of cases. We describe two novel pedigrees with moderate neutropenia. G-CSFR immunostaining was greatly reduced on patient neutrophils. G-CSF did not prolong neutrophil survival or enhanced reactive oxygen species generation, and STAT-3 phosphorylation was absent, while neutrophils did respond to granulocyte-macrophage colony-stimulating factor (GM-CSF). Despite a lack of G-CSF signaling, morphology and cellular proteomics were normal. We suggest the major role of G-CSF is not in myeloid differentiation, but in generation of sufficient number of committed progenitor cells for neutrophil release and their survival during inflammation, which corresponds with G-CSFR expression in myeloid cell fractions from bone marrow of healthy individuals.