Positioning of nucleosomes along DNA is an integral regulator of chromatin accessibility and gene expression in diverse cell types. However, the precise nature of how histone demethylases including the histone 3 lysine 4 (H3K4) demethylase, KDM5B, impacts nucleosome positioning around transcriptional start sites (TSS) of active genes is poorly understood. Therefore, to clarify the role for KDM5B in regulating nucleosome organization in ES cells, this study evaluated genome-wide changes in nucleosome positioning in KDM5B-depleted and control ES cells using micrococcal nuclease sequencing (MNase-Seq). These findings demonstrate that depletion of KDM5B leads to altered enrichment of nucleosomes around TSS regions and accessible chromatin regions (DNase I hypersensitive sites).