Patients with diffuse large B-cell lymphoma (DLBCL) who failed autologous stem cell transplantation (auto-SCT) generally have a poor prognosis. Allogeneic stem cell transplantation (allo-SCT) has been implemented to overcome this problem. We report clinical outcomes of allo-SCT in patients with de novo DLBCL who failed auto-SCT from four hospitals in Korea and Japan. Thirty patients were included. The median age was 39 (range, 22-59) years. The 5-year event-free survival (EFS) and overall survival (OS) after allo-SCT were 37.9 % and 42.6 %, respectively. There was only a single event beyond 12 months in the Kaplan-Meier curve of EFS. Non-relapse mortality (NRM) was reported in five patients (16.7 %). In the multivariate analysis, the risk factors for EFS were prior chemotherapy lines ≥ 5 (p = 0.010) and chemo-resistant disease (p = 0.007). The risk factors for OS were chemo-resistant disease (p = 0.024) and Eastern Cooperative Oncology Group performance status 2 (p = 0.005). NRM was associated with prior chemotherapy lines ≥ 5 (p = 0.042), chemo-resistant disease (p = 0.009), and poor performance status (p < 0.001). In conclusion, allo-SCT showed considerable efficacy in patients with DLBCL whose disease was relapsed or progressed after auto-SCT. Our data suggest that allo-SCT could be a viable treatment option if patients have fewer lines of prior chemotherapy, chemo-sensitive disease, and/or good PS.