A collection of ChIP-seq and chromatin accessibility data (DNase-seq and ATAC-seq) including 13366 human and 9953 mouse samples. Cistrome DB contains data which have been carefully curated and processed with a streamlined analysis pipeline and evaluated with comprehensive quality control metrics. A user-friendly web server allows data query, exploration and visualization. Cistrome DB provides a manually curated metadata annotation, presents analysis results, including a peak file, a read density file, motif scan results, putative target genes and summaries of the distribution of peaks. It provides comprehensive QC metrics at the read, peak and annotation levels and provides functions to analyze and visualize these samples. Users can directly send data to the Cistrome analysis pipeline (Cistrome AP) or load data to the UCSC and WashU genome browsers for visualization.