Abstract： Objective To evaluate the efficacy and feasibility of Flu/ivBu/Tl" conditioning regimen for the treatment of refractory or relapsed acute non-lymphocytic leukemia in patients receiving allogeneic hematopoietie stem cell transplantation. Methods Seven patients with refractory or relapsed acute non-lymphocytic leukemia received HLA identical peripheral blood hematopoietie stem cell transplantation (PBSCT) following Flu/ivBu/TY conditioning regimen, which consisted of fludarbine, busulfex and thiotepa. All patients received cyclos-porin A (CsA) and mycophenolet mofetil (MMF) for prophylaxis of graft - versus - host disease (GVHD). Results The Flu/IVBu/TT regimen was tolerated very well, without severe regimen related toxicity. In the 31-month median follow-up duration, 5 of 7 patients were a-live in disease-free situation. Conclusion The Flu/ivBu/TT conditioning regimen reduced transplantation-related toxicities and offered high long-term disease-free survival, and was tolerated very well. Allogeneie hematopoietie stem cell transplantation using Flu/ivBu/TT condition-ing regimen is a safe and effective option for the patients with refractory/relapsed acute non-lymphocytic leukemia.