For patients with acute myeloid leukemia (AML), allogeneic hematopoetic stem cell transplantation (HSCT) is one of the most potent treatment options currently available. In order to overcome the high risk of fatal treatment-related complications, reduced intensity and nonmyeloablative conditioning regimens for allogeneic HSCT are currently being explored in various hematological malignancies including AML. At least for allogeneic HSCT in AML, the optimal dose-intensity of preparative regimens for disease control at an acceptable rate of treatment-related lethal complications has not been determined. The investigators, therefore, evaluated reduced intensity myeloablative conditioning with 8 Gy TBI and fludarabine in AML patients considered ineligible for conventional conditioning in a phase 2 trial (data published in BLOOD by Stelljes et al., 2005). The results suggest that with 8 Gy TBI/fludarabine, conditioning related and unrelated donor transplants can be performed in AML patients in first or second complete remission (CR) with a remarkably low 2-year non relapse mortality (NRM) and satisfactory disease control. Based on these data a randomized phase 3 trial for patients with AML in CR≥2 is currently being conducted by the Cooperative German Transplant Study Group comparing TBI 8 Gy/fludarabine to conventionally dosed conditioning with TBI 12 Gy/cyclophosphamide.