We retrospectively analyzed 81 relapsed or refractory adult T-cell leukemia-lymphoma (ATL) patients who received salvage therapy in our institution between 2000 and 2010. These patients had received chemotherapy, radiation, or hematopoietic stem cell transplantation (HSCT) as an initial treatment, and were then given chemotherapy, radiation, HSCT, or donor lymphocyte infusion (DLI) as salvage therapy. Median survival time was 3.9 months. Of 5 long-term survivors, who survived more than 2 years after the first salvage therapy, 4 patients received HSCT or DLI, and the other was given mogamulizumab as the salvage therapy. For patients with relapsed or refractory ATL, HSCT/DLI is a promising treatment for achieving long-term survival. Mogamulizumab may be the good choice for those who are ineligible for HSCT.