Olfactory receptors (ORs) are the largest family in the genome, and the first of a widening range of chemosensory receptors (CRs) in other chemosensory organs. ORDB began as a database of vertebrate OR genes and proteins and continues to support sequencing and analysis of these receptors by providing a comprehensive archive with search tools for this expanding family. Because of the associated growth of interest in other CRs, the database has grown over the years to include a broad range of chemosensory genes and proteins, that includes in addition to ORs the taste papilla receptors (TPRs), vomeronasal organ receptors (VNRs), insect olfactory receptors (IORs), Caenorhabditis elegans chemosensory receptors (CeCRs), fungal pheromone receptors (FPRs) [these are informal abbreviations for tracking in ORDB, pending development of consensus nomenclature by the field].