There has been a great progress in the understanding in the pathogenesis of cancer due to the advancement of genetic and molecular methods. Under this progress, genetic and molecular assays have been incorporated into the diagnoses of leukemia and lymphoma. Moreover, the understanding of molecular aberrations in hematologic malignancies also brought the development of targeted agents for the treatment of leukemia and lymphoma. Chronic myeloid leukemia (CML) is one of myeloproliferative disorders and is caused by the presence of Philaldelphia chromosome, t(9;22), which produces an oncopreotein bcr-abl and induces the dysregulated proliferation of myeloid cells. Imatinib, a tyrosine kinase inhibitor targeting bcr-abl and inhibiting the phosphorylation of its downstream signaling pathways, was approved by FDA in May, 2001 for the treatment of CML refractory to interferon therapy. The introduction of imatinib not only improved the survival of CML patients but also changed the treatment modality for CML, replacing stem cell transplantation as the first choice for treating CML. With the identifications of genetic and molecular characteristics in various hematologic malignancies, many target therapies have been developed to treat leukemia and lymphoma, either as a single agent or combined with chemotherapy. In this session, the use of target therapy in hematologic malignancies will be introduced and discussed.