Matched unrelated or matched sibling donors can lead to comparable transplant survival, according to a single-center research study of 108 patients with AML (n=63) and MDS (n=45). In this study of reduced-intensity HCT, median age at transplant was 57 years (range, 20-68), and donors and patients were matched at high resolution at 10/10 HLA loci. Unrelated donor recipients were more likely to receive anti-thymoglobulin (ATG) than sibling donor recipients: 68% vs. 44%, respectively (p=0.026). Donor age was significantly lower for recipients receiving cells from unrelated donors than those with sibling donors: 30 vs. 52 years, respectively (p<0.0001). After adjustment for age, cytogenetic risk, ATG, and number of CD34+ cells infused, donor type still did not influence three-year overall survival: Sibling donor 45%; unrelated donor 49%; (p=0.98).