Allo-SCT is used to exploit GVL effect in high-risk relapsed non-Hodgkin's lymphoma (NHL). Here, we retrospectively analyzed 34 high-risk NHL patients who underwent auto-SCT followed closely by reduced-intensity allo-SCT ('tandem auto-allo') from January 2002 to November 2010. The search for an allogeneic donor was started at the beginning of salvage regimen. Median patients' age was 47 (27-68) years; histotypes were: diffuse large B-cell n ¼ 5, follicular n ¼ 14, transformed follicular n ¼ 4, mantle-cell n ¼ 5, plasmocytoid lymphoma n ¼ 1, anaplastic large T-cell n ¼ 2, peripheral T-cell n ¼ 3. Donors were HLA-identical siblings (n ¼ 29) or 10/10-matched unrelated individuals (n ¼ 5). Median interval between auto-SCT and allo-SCT was 77 days . At a median follow-up of 46 (8-108) months since allo-SCT, 5-year OS is 77% (61-93) and PFS is 68% (51-85). Disease relapse or progression occurred in six patients, 100-day TRM was 0%, 2-year TRM incidence was 6%. In conclusion, tandem transplantation is feasible in high-risk NHL patients having a HLA-identical donor. This approach could represent a suitable therapeutic option for those patients with high-risk NHL potentially benefitting from further therapy after auto-SCT. Donor searches should be started promptly whenever such an approach is chosen. Keywords: non-Hodgkin's lymphoma; tandem; autologous; allogeneic; SCT INTRODUCTION High-dose therapy followed by auto-SCT is the standard of care for most relapsed non-Hodgkin's lymphoma (NHL) patients. 1,2 Unfortunately, relapse after auto-SCT remains the most important cause of treatment failure. Allogeneic hematopoietic SCT (allo-SCT) yields lower relapse rates compared with auto-SCT because of its GVL effect 3-6 but on the other hand, its feasibility could be limited by the TRM. 7,8 Some risk factors have been associated with poor outcome after salvage therapy followed by auto-SCT, 1,2,9-11 underlying the need for improving prognosis of these patients. A tandem autologous-allogeneic transplantation approach could have the advantage of combining cytoreduction with GVL effect with the aim of ameliorating the outcome of those patients for whom high-dose chemotherapy followed by auto-SCT gives unsatisfactory results.The aim of this retrospective study is to evaluate the feasibility and safety of tandem 'auto-allo' in poor prognosis NHL patients.