This method probes DNA accessibility with hyperactive Tn5 transposase, which inserts sequencing adapters into accessible regions of chromatin. Sequencing reads can then be used to infer regions of increased accessibility, as well as to map regions of transcription factor binding and nucleosome position. The method is a fast and sensitive alternative and complement to MNase-seq, FAIRE-seq and DNase-Seq for assaying chromatin accessibility genome-wide or for assaying nucleosome positions in accessible regions of the genome.