The progressive and fatal course of chronic myelogenous leukemia has not been affected significantly by chemotherapeutic agents that control the benign phase of the disease. Combination chemotherapy and aggressive treatments may offer some advantages: however, these approaches do not appear to produce stable suppression of Ph1 chromosome or to prolong chronic phase and survival of these patients. Only allogeneic bone marrow transplantation has been demonstrated to be capable of inducing a stable, complete suppression of Ph1+ cells. Recently alpha Interferons (IFN) have been shown to control myeloid proliferation in patients with CML and to determine a progressive and persistent decline of Ph1+ bone marrow cells in some cases. The hypothesis that in most newly diagnosed patients with CML various amount of Ph1 negative cells must still be present, albeit in suppressed state in the bone marrow (BM) or in the peripheral blood (PB), have led some Authors to treat patients with high-dose chemotherapy followed by reinfusion of stem cells collected at diagnosis or after a response to cytoreductive treatments. We report 34 patients with CML treated in chronic phase with Busulohan and Melphalan conditioning regimen followed by reinfusion of BM or PB stem cells.