The Eukaryotic Promoter Database (EPD), developed at the Weizmann Institute of Science in Israel and currently maintained at the Swiss Institute for Experimental Cancer Research, is an annotated collection of eukaryotic POL II promoters intended to assist experimental researchers as well as computer analysts in the investigation of eukaryotic transcription signals. Promoters are included in EPD if they are recognized by eukaryotic RNA POL II, active in a higher eukaryote, experimentally defined or homologous and sufficiently similar to an experimentally defined promoter, biologically functional, available in the current EMBL release, and distinct from other promoters in the database. Database entries (searchable by organism, homology group, sequence, keywords, references, etc.) include promoter identifications and descriptions, information on the experimental evidence, various kinds of promoter classifications and regulatory properties, as well as bibliographic references and cross-references to other databases. The EPD Website also features yearly-updated base frequency matrices for major eukaryotic promoter elements, a user manual, and a link to a complementary database called EPDX, which allows users to view available gene expression data for human EPD promoters.