Chronic neutropenias (Nps) encompass a diverse group of disorders marked by persistently reduced neutrophil counts, with varying etiologies, clinical presentations, and prognoses. This chapter reviews the classification, pathophysiology, and diagnostic approach to congenital, acquired, and likely acquired neutropenias. Congenital neutropenias, often linked to genetic mutations such as ELANE or HAX1, typically present in early life with recurrent infections and carry a risk of progression to myelodysplastic syndrome (MDS) or acute leukemia (AL). Acquired forms, including autoimmune and idiopathic neutropenias, are more prevalent in infancy and adulthood, often resolving spontaneously or persisting with mild symptoms. A new category, “likely acquired neutropenia,” has emerged, bridging immune and genetic etiologies. Diagnostic algorithms emphasize the exclusion of secondary causes and the use of advanced molecular testing. Granulocyte colony-stimulating factor (G-CSF) remains the cornerstone of therapy in severe cases, with hematopoietic stem cell transplantation (HSCT) reserved for high-risk patients. Emerging genetic insights are reshaping management strategies and risk stratification.