Eighteen patients (men=14; women=4) with natural killer (NK)/T-cell lymphomas (CR1, N=9; CR2, N=7; PR, N=1; progressive disease, N=1) undergoing allogeneic haematopoietic SCT (HSCT) (myeloablative, N=14; reduced intensity, N=4) were analyzed. With a median follow-up of 20.5 months, the 5-year OS was 57% and 5-year EFS was 51%. The use of the SMILE regimen pre-HSCT was the most important positive prognostic indicator, resulting in significantly superior OS and EFS (P<0.01). Acute GVHD had a significant negative impact on OS (P=0.03). CR1 and CR2 patients had similar survivals, but all patients who were not transplanted in remission died. Chronic GVHD, International Prognostic Index, disease stage, primary sites of involvement, conditioning regimen and source of HSC did not affect survival. Although allogeneic HSCT leads to reasonable survival for NK/T-cell lymphoma patients, results need to be compared with those in patients receiving L-asparaginase-containing regimens. Novel prognostic models incorporating biomarkers, such as circulating EBV DNA, are needed to identify high-risk patients who may benefit from allogeneic HSCT.