Although allo-HSCT is the key strategy to cure patients with mature T- and NK-cell lymphomas/leukemia, especially those with relapsed/refractory diseases, there is no consensus strategy for donor selection. We retrospectively analyzed the allo-HSCT of 111 patients in 15 Japanese institutions as a multi-institutional joint research. Thirty-nine patients received bone marrow or peripheral blood stem cell transplantation from related donors (rBMT/rPBSCT), 37 received BMT/PBSCT from unrelated donors (uBMT/uPBSCT), and 35 received cord blood transplantation (CBT). Overall survival (OS) and progression-free survival rates (PFS) at 4 years were 42% and 34%, respectively. Cumulative incidences of relapse and non-relapse mortality were 43% and 25%. In multivariate analysis, CBT showed comparable OS with rBMT/rPBSCT (rBMT/rPBSCT vs. CBT: HR, 1.63; P=0.264) and better OS compared to uBMT/uPBSCT HR, 2.99; P=0.010), with a trend for lower relapse rate (rBMT/rPBSCT vs CBT: HR, 2.60; P=0.010; uBMT/uPBSCT vs CBT: HR, 2.05; P=0.082). This superiority of CBT was more definite in on-disease patients (OS: rBMT/rPBSCT vs CBT: HR, 5.52; P=0.021, uBMT/uPBSCT vs CBT: HR, 6.80; P=0.007). Better disease control was also strongly associated with better OS and PFS with lower relapse rate. In conclusion, allo-HSCT is beneficial for the survival of patients with mature T- and NK-cell lymphomas/leukemia if performed in a timely fashion. Since CBT showed favorable survival with a lower relapse risk, it could be a preferred alternative choice, especially in on-disease patients.Copyright © 2020. Published by Elsevier Inc.