3-O-β-d-Xylopyranosyl-l-serine (xylosylserine) was synthesized by the following three-step procedure: 1) 2,3,4-tri-O-benzoyl-α-d-xylopyranosyl bromide (benzobromoxylose) was condensed with N-carbobenzoxy-l-serine benzyl ester using the silver triflate-collidine complex as promoter; 2) the N-carbobenzoxy and benzyl ester groups in the resultant glycoside were cleaved by transfer hydrogenation with palladium black as catalyst and ammonium formate as hydrogen donor; and 3) the benzoyl groups were removed with methanolic ammonia. Xylosylserine was obtained in an overall yield of 70%. O-β-d-Galactopyranosyl-(1-4)-O-β-d-xylopyranosyl-(1-3)-l-serine (galactosylxylosylserine) was also synthesized by this methodology and was characterized by 2-dimensional (2D) NMR spectroscopy techniques. The two serine glycosides (xylosylserine and galactosylxylosylserine) were used in detection and partial purification of galactosyltransferase I (UDP-d-galactose:d-xylose galactosyltransferase) from adult rat liver. © 1987 Glycoconjugate Journal.