Current reduced intensity conditioning regimens have been able to decrease TRM (treatment related mortality) but suffer from increased rates of disease relapse. Disease burden at transplantation, as measured by percent myeloblasts, predicts relapse. Current regimens employ fludarabine and busulfan with various adjutants, but these agents are not part of the usual armamentarium used versus leukemia and have questionable anti-leukemic activity. By substituting clofarabine and cytarabine, a combination with proven anti-leukemic activity in the relapsed and refractory setting as well as activity versus MDS, as the back bone of the regimen we hope overcome residual disease and improve post-transplant relapse rates. Furthermore the principal toxicity of this regimen is myelosuppression, which should be abrogated by the infusion of stem cells. Thymoglobulin is included due to its minimal contribution to toxicity but significant benefits in engraftment, and controlling acute and chronic GVHD, which are major contributors to TRM and disease specific activity in MDS.