Two D-xylose reductase (XR) genes, xyrA and xyrB, of Candida tropicalis IFO 0618 were cloned and sequenced. Each XR gene had an open reading frame consisting of 324 amino acids (972 bp). The deduced amino acid sequences of each XR gene were very similar to each other, except for three amino acids. The molecular weights of the deduced gene products were 36,551 (xyrA) and 36,596 (xyrB). These genes were 73.0% identical to the Pichia stipitis XR gene.