A 77-yr-old Chinese man was diagnosed as chronic neutrophilic leukemia (CNL). The patient showed sustained mature neutrophilic leukocytosis, splenomegaly, high leukocyte alkaline phosphatase score, elevated serum vitamin B12 and uric acid, myeloid hyperplasia and absence of philadelphia chromosome in the bone marrow. There was no evidence of any underlying infection or malignancy to be considered that this condition was a leukemoid reaction. The neutrophil function showed decreased phagocytic activity, decreased myeloperoxidase content and increased release of the enzyme after stimulation. CNL is not a common disease, literature review and analysis of 31 cases will be reported.