Unmanipulated haploidentical transplantation (Haplo-SCT) using post-transplantation cyclophosphamide (PT-Cy) represents an alternative for patients with high-risk diseases lacking HLA-identical donor. Although it provides low incidences of GVHD, the efficacy of Haplo-SCT is still questioned, especially for patients with myeloid malignancies. Thus, we analyzed 60 consecutive patients with refractory (n=30) or high-risk CR (n=30) AML or myelodysplastic syndromes (MDSs) who underwent PT-Cy Haplo-SCT. The median age was 57 years (22-73 years), hematopoietic cell transplantation comorbidity index was ⩾3 in 38 patients (63%) and Haplo-SCT was the second allogeneic transplantation for 10 patients (17%). Although most of patients received PBSC as graft source (n=48, 80%), we found low incidences of grade 3-4 acute (2%) and severe chronic GVHD (4%). Among patients with high-risk CR diseases, 1-year non-relapse mortality, cumulative incidence of relapse, progression-free and overall survivals were 20%, 32%, 47% and 62%, respectively. In patients with refractory disease, corresponding results were 34%, 35%, 32% and 37%, respectively. We conclude that PT-Cy Haplo-SCT could provide promising anti-leukemic effect even in the setting of very advanced diseases. Thus, it represents a viable alternative for high-risk AML/MDS patients without HLA-identical donor.