Chromosomal assignments of the genes for the human endothelin family, the endothelin-1 gene (EDN1), the endothelin-2 gene (EDN2), and the endothelin-3 gene (EDN3), were accomplished by in situ hybridization to human metaphase chromosomes using a 3H-labeled human preproendothelin cDNA probe for each endothelin. The chromosomal assignment of the EDN2 was also performed by Southern blot analysis of somatic cell hybrid DNAs. EDN1, EDN2, and EDN3 were mapped to 6p23-p24, 1p34, and 20q13.2-q13.3, respectively.