In all, 18 patients (30-56 years; median 49) with MDS underwent allogeneic HSCT from related (n=12) or unrelated (n=6) donors after a conditioning regimen comprising thiotepa, cyclophosphamide, and TBI. GVHD prophylaxis consisted of cyclosporine (n=15) or tacrolimus (n=3) with short-course methotrexate. Four patients had low-risk disease (refractory anemia or complete remission after chemotherapy) and 14 patients had high-risk disease (RAEB, RAEB-t, or AML). Grade II-IV acute GVHD developed in six patients and chronic GVHD in 10. With a median follow-up of 31 months, the 2-year survival probability is 75% for low-risk patients and 57% for high-risk patients. One patient died of leukemia and six of treatment-related causes. This conditioning regimen requires further study in patients with MDS.