In summary, it can be expected that the availability of unrelated donors will increase the number of CML patients that can be treated curatively with allogeneic BMT. Hydroxyurea has replaced busulfan as first line treatment in CML since it prolongs survival. Ongoing randomized studies comparing IFN-based treatment regimens with standard chemotherapy or IFN-monotherapy probably will answer the question whether IFN can cure a small percentage of CML patients and whether this small percentage can be increased by additional chemotherapy. The present attempts to improve prognostic scores and to apply them to early treatment decisions will allow treatment adaptation more individually. The implications of endogenous retroviral sequences expressed in CML cells are not known now, but may be far reaching.