We analyzed the outcome of stem cell transplantation (SCT) for 59 acute myeloid leukemia (AML) patients with t(8;21). The 5-year overall and disease-free survival (OS and DFS) were 70.2 and 68.4%, respectively. The 5-year cumulative incidence of relapse (CIR) and nonrelapse mortality were 16.9 and 13.6%, respectively. OS and DFS in the reduced-intensity conditioning (RIC)-SCT group (70.4%) were not different from in the autologous SCT (ASCT) group (72.4 and 69.0%, respectively). Age was a factor affecting OS (p = 0.007) and DFS (p = 0.008) in the ASCT group, but not in the RIC-SCT group. In the ASCT group, lack of the X chromosome (-X) and an age of >50 years were associated with inferior survival; however, these differences disappeared in the RIC-SCT group. CIR was significantly higher in patients with -X than in those without -X only in the ASCT group (p = 0.038), i.e. not in the RIC-SCT group. ASCT and RIC-SCT are equally effective for the intensification of postremission treatment of AML patients with t(8;21). The subgroups with advanced age or -X should be preferentially considered for RIC-SCT, rather than ASCT. Further investigations with randomized prospective trials of a sizeable study population are warranted.