Endothelin 3 is a novel vasoactive peptide of unique structure and belongs to the endothelin gene family. Though it mainly functions as a vasoconstrictor/pressor, it plays a major role in a wide variety of other biological functions, possibly as a novel neuropeptide. Studies with human-mouse somatic cell hybrids have suggested that the gene EDN3 is localized on human chromosome 20. We confirmed this localization and regionally mapped the gene to the region 20q13.2-q13.3.