From a bank of 50,000 HLA typed French bone marrow donors, 125 transplants have been performed since 1986, with HLA AB and DR--identical MLC--negative donors. The median age was 25 years and the diagnosis was CGL in 59 cases, ALL in 22 cases, AML in 17 cases, SAA in 7 cases, inborn errors in 7 cases and others in 13 cases. Most of the patients received a standard conditioning regimen according to their diagnosis. The prophylaxis of GVHD was methotrexate and cyclosporine A in 77 cases; in addition to this combination 44 patients received an anti-IL2 receptor monoclonal antibody from day +1 to day +28. There was no difference between the two groups as regards the incidence and severity of GVH or survival. The actuarial survival was 36% with a median follow up of 300 days. Unlike matched sibling grafts, the usual prognostic factors such as stage of disease or age were not found to significantly modify the incidence of GVHD, which was 75%. The results of matched unrelated donor transplants are reasonably good, but must be improved by a better selection of donors and better prevention of GVHD.