Background: We assessed the impact of donor type in acute myeloid leukemia (AML) patients transplanted with 2 Gy total body irradiation (TBI)-based nonmyeloablative conditioning regimen.Experimental Design: Data from 1,715 adult patients, with AML in CR1 or CR2 were included in this retrospective survey.Results: Donors consisted either of HLA-matched sibling donors (MSD, n ¼ 701), 10/10 HLA-matched unrelated donors (MUD, n ¼ 611), HLA-haploidentical donors (haplo, n ¼ 112) or single or double umbilical cord bloods (CBT, n ¼ 291). Chronic graft-versus-host disease (GVHD) was less frequent in CBT (28%) and in haplo (30%) patients than in MSD (50%) and MUD (51%) recipients (P < 0.001). Two-year incidence of relapse was 32%, 30%, 34%, and 34% in MSD, MUD, CBT and haplo patients,