We observed an overall response rate of 56% (5 of 9) including Marrow Complete Remission (mCR) (n=3), partial cytogenetic response (n=2), stable disease (SD) (n=3), and progressive disease (PD) (n=1). Toxicity was minimal. The majority of grade 3 events were infectious (36%) or gastrointestinal (25%) and grade 4 events were limited to cytopenias. Donor NK cell expansion was not observed but endogenous NK cell killing was increased and was present after both cycle 1 and cycle 2.Our older high-risk MDS population tolerated sequential decitabine, vorinostat, and haploidentical NK cell infusions with IL-2 administration and experienced good response rates. Unlike previous studies using more potent lymphodepletion, we did not observe donor NK cell expansion with this outpatient regimen and thus further study with a more intensified immunosuppressive platform is warranted.