Background Clinical application of allogeneic stem cell transplantation (allo-SCT) for lymphoma patients (pts) has been hampered by its high mortality rate. In order to explore and establish safe and efficient procedures, reduced-intensity stem cell transplantation (RIST) has been incorporated in recent protocols for lymphoma. Here we retrospectively analyzed our single institute experiences of allo-SCT for lymphoma.Results Between 1999 and 2005, 127 allo-SCTs, including 94 RIST (74%), were performed for lymphoma in our single institute. The number of each pathological classification and the one in which RIST was used, which is shown in each parenthesis, were PTCL (non-ATLL) 15 (RIST 13), ATLL 25 (18), NK/T 3 (2), FL 36 (29), MCL 6 (5), DLBCL 23 (17), LPL 1(1), HL 5 (5) and LBL 13 (4). Most patients were not eligible for autologous transplantation (auto-SCT) because of relapse after auto-SCT or chemo-resistant disease. Transplant-related mortality (TRM) were 16% in RIST and 45% in conventional stem cell transplant (CST) (p<0.001), and it was as high as 54% in aggressive lymphoma pts treated with CST (n=26). 3-year OS and PFS of FL, PTCL including 2 ALCL and 1 AILT, and ATLL were 80.6±6.6% and 80.6±6.6%, 46.7±12.9% and 60.0±12.6%, 46.5±10.3 and 57.1±10.6%, respectively, with the median follow-up of 737 days (range, -4–2628) in all these pts. Pts with other histology had poor outcomes and the numbers of pts surviving more than 1 year were HL 1 (20%), MCL 2 (33%), DLBCL 7 (30%), NK/T 1 (33%) and LBL 3 (23%). 5 pts with DLBCL were treated with auto-SCT/RIST tandem transplantation according to in-house protocol, and 4 out of 5 were alive in current CR with median follow-up of 749 days (range, 580–1038).Discussion Since RIST was associated with lower TRM than CST, it could be applied safely in heavily treated pts with refractory lymphoma. Most pts with DLBCL, NK/T, and LBL relapsed or died of disease. However, pts with FL, PTCL and ATLL, even in chemo-refractory cases, had durable remissions after RIST. In refractory DLBCL, de-bulking of the tumor by prior auto-SCT might be promising.Conclusions RIST could be performed comparatively safely. Notably, PTCL, both ATLL and non-ATLL, were newly highlighted as a good indication of RIST and should be further investigated. [Display omitted]