Chronic myeloid leukemia (CML) is considered a common blood cancers and accounts for approximately 15–20% of the total cases of leukemia. Recent studies indicated that above 95% of patients suffering of CML have been found with a distinctive Philadelphia chromosome that originates from a mutual translocation between both arms of chromosomes 9 and 22. During this mutation the translocation of the ABL gene located on chromosome 9 get transferred to the breakpoint cluster region (BCR) of chromosome 22 as an effect of a joined BCR-ABL gene. Furthermore, BCR-ABL oncogene is characteristically found in CML, causing cells to divide uncontrollably and inducing severe consequences among CML patients. In line with this, applying quantification technique of the BCR-ABL gene using molecular approaches is crucial for patient controlling, initiation of the proper treatment, measurement of response to therapy, and prediction of relapse. Of greater significance, molecular assay and monitoring of the BCR-ABL gene in CML using quantitative RT-PCR provides physicians with essential diagnostic and prognostic information.