So far the impact of cytogenetics risk on outcome in the context of reduced intensity conditioning (RIC) allo-SCT has been poorly studied. We have identified 378 AML patients in first CR who underwent RIC allo-SCT from an HLA-matched sibling donor between 2000 and 2007 reported to the European Group for Bone and Marrow Transplantation and for whom detailed cytogenetics data were available (good risk: n=21; intermediate risk: n=304; and poor risk: n=53). With a median follow-up of 24 months (range: 1-93), 2-year non-relapse mortality, relapse rate (RR), leukemia-free survival (LFS) and OS were 14%, 31%, 55% and 61%, respectively. Cytogenetics was significantly associated with RR (good risk: 10%; intermediate risk: 28%; and poor risk: 55% at 2 years, P<0.0001) and LFS (good risk: 64%; intermediate risk: 57%; and poor risk: 38% at 2 years, P=0.003). In a multivariate analysis, RR and LFS were significantly higher and lower, respectively, in the high-risk cytogenetics group (P=0.001, P=0.004) and in patients with a higher WBC at diagnosis (>10 × 10(9)/L) (P<0.001, P=0.004). As documented in the setting of myeloablative allo-SCT, patients with poor cytogenetics had increased RR and decreased LFS after RIC allo-SCT, requiring new prospective strategies to improve results in this subgroup.