The chromosomal localization of the human endothelin converting enzyme gene (ECE1) has been identified. Southern blot analysis of human genomic DNA from human × mouse somatic cell hybrids demonstrated that ECEl maps to chromosome 1. Fluorescence in situ hybridization of a digoxigenin-labeled human ECE1 probe to normal human metaphase chromosomes showed that the gene is located within chromosome band 1p36.1. © 1996 S. Karger AG, Basel.