Allogenic bone marrow transplantation (BMT) was performed in 8 patients with B chronic lymphocytic leukemia (CLL): 6 males and 2 females with a median age of 41 years (37 to 46). Seven patients were resistant to previous therapy and were grafted in the evolutive phase. Only 1 patient was grafted without any previous treatment. At the time of BMT 5 patients were classified according to the Rai classification in stage IV, 1 in stage III and 2 in stage 1. The delay between diagnosis and BMT was 47 months (5 to 68). Graft versus host disease (GVHD) prophylaxis was methotrexate (1 patient), cyclosporine (2 patients), methotrexate + cyclosporine (3 patients), cyclosporine + physical removal of T cells (2 patients). The conditioning regimen was standard for 5 patients, reinforced for 3 patients with Chlorambucil (1 patient) and etoposide (2 patients). A successful engraftment was obtained in all cases. The lymphocytosis decreased slowly and disappeared from day 0 to day 28. All patients developed an acute GVHD 5 of which resolved. Three patients died: 2 of acute GVHD and 1 of intracerebral hemorrhage. Five patients are alive in persistent complete remission without clinical symptoms and with normal peripheral blood and normal bone marrow. The median follow-up is 27 months (13-53). This small series suggests that allogeneic BMT should be investigated in selected patients as possible curative treatment of CLL.