Patients with relapsed PTCL have a poor prognosis. We had previously shown the existence of a graft-versus-lymphoma effect against PTCL (J Clin Oncol, 2004). In the present report, we extended our previous observations to 26 patients (pts) receving allo-SCT. All patients received several courses of debulkying chemotherapy (usually 3 DHAP and/or high-dose chemotherapy) followed by the same RIC regimen containing thiotepa (10 mg/kg), fludarabine (60 mg/ms) and cyclophosphamide (60 mg/kg). GVHD prophylaxis consisted of cyclosporine A and short-course methotrexate. Patients’ median age was 45 years (range, 15–64). Histologic PTCL subtypes included: PTCL not otherwise specified (n=12), ALCL (n=7), angioimmunoblastic (n=3), others subtypes (n=4). Twenty-two pts (84%) received transplant from HLA-identical sibling, 3 from haploidentical sibling and one from unrelated donor. The median time from diagnosis to transplantation was 17 months. Thirteen patients (50%) had failed a previous auto and the majority received at least 2 lines of chemotherapy before allo-SCT. Seven (27%) and 13 pts (50%) were in CR and PR at the time of allo-SCT, respectively. At median follow-up of 27 months (range, 8–73), 17 (65%) were alive (n=14 in CR) and 9 died (n=6 disease, n=3 toxicity). The estimated 3-year TRM was 13%. The estimated 5 year OS and PFS projections were 61% (95% CI, 41–81%) and 51% (95% CI, 30–72%), respectively. Relapses occurred in the first 6 months after allo-SCT and we did not observe differences in PFS between specified and unspecified variants. De-novo acute GVHD (II/IV) and chronic GVHD incidence were 28% and 24%, respectively. Eight patients received DLI, 6 for relapse, 1 pre-emptive, 1 for infection: 3 responded (n=1 CR, n=2 PR). Following DLIs, 4 patients developed GVHD with associated a clinical response. In conclusion, our data indicate: 1) long-term disease control was achieved in patients with an aggressive subtype of NHL; 2) although optimal therapeutic strategies for relapsed PTCL are yet to be defined, further prospective evaluation of allo-SCT is required.