PURPOSE: To investigate the influence of donor type (human leukocyte antigen [HLA] -identical sibling donor versus HLA-A-, HLA-B-, HLA-Cw-, HLA-DRB1-, and HLA-DQB1-identical unrelated donors, or so-called 10/10) on the outcome of patients who underwent allogeneic stem-cell transplantation (alloSCT), adjusting for other prognostic factors, in patients with standard-risk hematologic malignancy. PATIENTS AND METHODS: Between March 2000 and January 2003, we prospectively investigated the outcome of 236 consecutive patients with standard-risk malignancy from 12 French centers. Fifty-five patients underwent alloSCT from an unrelated HLA-identical donor at the allelic level, whereas 181 patients received an alloSCT from an HLA-identical sibling. Diagnoses included acute leukemia (n = 175), chronic myeloid leukemia (n = 43), and myelodysplastic syndrome (MDS; n = 18). All patients received unmodified marrow graft following myeloablative conditioning with cyclophosphamide and total-body irradiation. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and short-course methotrexate in all patients. RESULTS: In multivariable analysis, overall survival and transplantation-related mortality were adversely influenced by recipient cytomegalovirus (CMV) -positive serology, age of donor older than 37 years, and the occurrence of acute grade > or = II GVHD. Event-free survival rates were lower for patients with recipient CMV-positive serology. Acute grades II to IV GVHD rates were higher for patients with chronic myeloid leukemia (CML). No factor was found to influence either relapse or acute grades III to IV GVHD. The effect of donor type was nonsignificant for all criteria. CONCLUSION: In patients with standard-risk malignancy, transplantation from unrelated HLA-allellically matched donors led to outcomes similar to those from HLA-identical sibling donors.