Circulating neutrophil numbers at homeostasis is a result of a balance between the chemokine signaling axes, CXCR4 and CXCR2. These receptors are crucial in mediating neutrophil trafficking from the bone marrow (BM), thereby regulating the number of circulating neutrophils. While the CXCR4-CXCL12 axis mediates neutrophil retention in the BM, the chemokine axis implicated in the regulation of neutrophil egress is CXCR2 and its ligands. A defect in these signaling axes significantly impacts on the homeostasis of circulating neutrophil numbers. Clinical studies of a rare congenital immunodeficiency disorder known as WHIM (Warts, Hypogammaglobulinemia, Infections, Myelokathexis) syndrome due to a gain-of-function mutation in the CXCR4 receptor in human patients, is characterized with severe neutropenia. Although results from these studies attributed the observed neutropenia to increased retention of cells in the BM (myelokathexis), there is still a lack of mechanistic understanding of the disease pathogenesis. To address this question, we have systematically characterized the mouse model of WHIM syndrome (CXCR4+/mutant(1013) mice). To this end, we observed that CXCR4+/mutant(1013) mice displays an increased accumulation of neutrophils in the BM resulting in neutropenia. We also provide direct evidence to show that the CXCR4 gain-of-function mutation did not have an effect on granulopoiesis but instead delays the egress of mature neutrophils from the BM. Using this model, we further dissect out the balance between the chemokine receptors, CXCR4 and CXCR2 in the context of WHIM syndrome, and found that the gain of CXCR4 receptor function did not influence the expression or functionality of the CXCR2 receptor. In summary, this study describes the role of CXCR4 in neutrophil homeostasis and implications for fundamental understanding of neutrophil biology and treatment for neutropenia.