Chronic myeloid leukemia (CML) was a well-known myeloproliferative neoplasm and a disease of haemopoietic stem cells due to BCR-ABL fusion protein arising from a translocation t(9;22), known as the Philadelphia chromosome. Imatinib (Gleevec), a selective small molecule inhibitor of Bcr-Abl kinase, has been confirmed as the standard drug therapy for CML. Discovery of imatinib led to the availability of a molecular-targeted therapy as a new model of cancer treatment and challenged the molecular target cancer treatment trend from non-targeted cytotoxic chemotherapy. We reviewed the advancement of chronic myeloid leukemia treatment in the area of imatinib.