This study compared the results of allogeneic peripheral blood stem cell transplantation (PBSCT) from unrelated and related donors, and involved 235 consecutive patients from ten centers between Jan 2004 and Dec 2008. Among these patients, 160 (68.1%) received a human leukocyte antigen-matched related PBSCT and 75 (31.9%), a matched unrelated PBSCT. The cumulative incidence of acute graft-versus-host disease (GVHD) was 43.9% for the related PBSCT and 59.3% for the unrelated PBSCT. Although the cumulative incidence of chronic GVHD was no different between the related (54.2%) and unrelated (64.9%) PBSCT, the cumulative incidence of extensive chronic GVHD was higher among the unrelated PBSCT (34.9%) than among the related PBSCT (17.0%). The overall survival rate at 4 years was 58.2% versus 49.1%, and the cumulative incidence of relapse was 28.4% versus 25.0% for the related and unrelated PBSCT, respectively. Among the factors examined, unrelated PBSCT, the CD34-positive cell count, and cytomegalovirus infection were all related with a higher incidence of extensive chronic GVHD. However, in a multivariate analysis, only unrelated PBSCT was identified as a risk factor for the development of extensive chronic GVHD (hazard ratio = 2.012; P value, 0.048). In conclusion, the survival and relapse incidence were not significantly different between the related and unrelated PBSCT.