Excessive growth of mature granulocytes in the bone marrow induces chronic myeloid leukemia. The excess neoplastic granulocytes travel massively into the peripheral blood and in the end invade the liver and spleen. The protein encoded on the Philadelphia chromosome by the newly created BCR-ABL gene interferes with normal cell cycle activities, including regulating cell proliferation. Philadelphia chromosome is present in 90 - 95 percent of chronic myeloid leukemia (CML) patients. Their involvement is often a vital indicator of persistent disease or posttreatment relapse. However, for the diagnosis of CML, the presence of the Philadelphia chromosome is not specific since it is also present in acute lymphocytic leukemia (ALL) and rarely in acute myeloid leukemia (AML). 1 Chronic myeloid leukemia is a myeloproliferative neoplasm (MPN) characterised by involvement of the fusion gene BCRABL1 located in the Philadelphia chromosome. In reactive neutrophilia or chronic neutrophilic leukemia, the Ph chromosome is pathognomonic to CML and is never registered.2,3