The invention provides a novel species of α-1,3-fucosyltransferase expressed by a gene cloned from animal cells, a cDNA coding for the α-1,3-fucosyltransferase, a method of detecting, or inhibiting the production of, the α-1,3-fucosyltransferase which involves the use of the cDNA, a recombinant vector containing the DNA as an insert, a cell harboring the recombinant vector, and a method of producing same. The α-1,3-fucosyltransferase of the invention is useful in the production of carbohydrate chains having useful physiological activity, for example sialyl Lewis x, and modifications thereof.