Two cDNA clones coding for human alpha-L-fucosidase, one from the coding region and the other primarily from the 3' untranslated region, were used to map the location of the alpha-L-fucosidase gene. Southern filter analysis of somatic cell hybrid lines mapped the structural gene to the short arm of human chromosome 1, and in situ hybridization to chromosomes of human leukocytes further localized the homologous area to the 1p36.1----p34.1 region, with the most likely location being the distal region of 1p34. Further Southern filter analysis detected a second site of homology on chromosome 2. This alpha-L-fucosidase-like site has been designated FUCA1L.