Chronic myelogenous leukemia (CML) is a hematologic malignancy characterized by an initial chronic phase of expanded clonal myelopoiesis followed by inevitable progression to accelerated phase and finally to fatal blast crisis. Although interferon therapy results in hematologic control of disease in most patients and major cytogenetic responses in 30% to 35%, resulting in better survival than with conventional therapy with hydroxyurea or busulfan, most patients have residual disease detectable by molecular methods. Allogeneic bone marrow transplantation may cure selected patients with CML and should be considered early in the course of disease. Newer approaches to therapy include autografting using mobilized peripheral blood stem cells. Selection and expansion of nonleukemic progenitors may improve outcome following autologous transplantation. Advances in understanding of mechanisms of action of antisense oligonucleotides, ribozymes, and tyrosine kinase inhibitors and the immunologic responses to CML cells are also likely to lead to novel approaches to therapy.