Between January 1983 and July 1997, 83 patients (35 female, 48 male) with a median age of 37 (19-57) years with chronic myelogenous leukemia (CML) were admitted for bone marrow transplantation (BMT) at the University hospital of Vienna. Fifty-six patients were in chronic phase, 17 in accelerated and 10 had blast crisis. Marrow donors were: HLA-identical siblings in 62 patients, 2-antigen mismatched related donor in 2, HLA-identical unrelated donors (MUD) in 17 and 1-antigen mismatched unrelated donor in 2 patients. The median time from diagnosis to BMT was 22 (2-91) months. Conditioning therapy consisted of cyclophosphamide (CY) and total body irradiation or CY and busulfan. For graft-versus-host disease (GVHD) prophylaxis methotrexate (MTX) alone, MTX and cyclosporine A (CSA), CSA alone or CSA and methylprednisone were given. Durable engraftment was documented in 75 of 77 patients (97%). As of July 31, 1997 48 patients are alive (58%), 36 (56%) after sibling transplantation with a median observation time of 77 months and 12 (63%) after MUD transplantation with a median observation time of 13 months. Overall survival for patients in chronic phase (CP) at time of BMT is 64%, 53% for patients in acceleration and 30% for patients in blast crisis (BC). Disease-free survival (DFS) after sibling BMT and unrelated donor transplantation is 53% and 58%, respectively. Ten patients (12%) experienced relapse of CML. Transplant-related mortality was 33% after sibling and 32% after MUD transplantation. Thus, sibling and unrelated donor BMT offer high cure rates with acceptable toxicity to patients with CML.