.alpha.-1,4-galactosyltransferase (CgtD) polypeptides, nucleic acids that encode the polypeptides, including a polypeptide from Campylobacter jejuni strain LIO87 have been isolated and characterized A method of producing a galactosylated saccharide comprising contacting an acceptor saccharide containing a terminal galactose, a donor substrate comprising a galactose moiety and one of the CgtD polypeptides is described.