The choice of primary treatment for patients with chronic myeloid leukemia (CML) diagnosed in chronic phase has become exceedingly difficult. There is little doubt that allogeneic stem cell transplantation can eradicate the leukemia and that a graft-versus-leukemia effect makes a major contribution to this result; conversely, only a minority of patients are eligible for transplantation, which still carries an appreciable risk for death or protracted illness. For most patients, interferon-alpha (IFN-alpha) prolongs life to some degree in comparison with hydroxyurea, but it is associated with considerable toxicity. The newly introduced tyrosine kinase inhibitor STI571 induces complete hematologic remission in almost all patients and is associated with a very high rate of cytogenetic response; its capacity to prolong life in comparison with IFN-alpha is not yet established. Here are reviewed some factors that predict survival after nontransplantation therapy and after allografting for CML in chronic phase. Two contrasting options are considered for managing the patient with newly diagnosed disease, and it can be concluded that, for now, allogeneic stem cell transplantation soon after diagnosis should continue to be offered as an option for selected patients. Further experience with the use of STI571 as a single agent or in combination with other antileukemic agents may alter the picture in the near future.