The configuration of glycosidic linkages in a number of reducing disaccharides has been determined by converting each compound to the corresponding 2-O-glycosyl-glycerol, the configuration of which was readily established. Compounds examined include 3-O-β-D-galactopyranosyl-D-galactose, 3-O-α-D-galactopyranosyl-L-arabinose, 3-O-β-D-arabopyranosyl-L-arabinose, 2-O-β-D-xylopyranosyl-L-arabinose, 3-O-α-D-xylopyranosyl-L-arabinose, and 4-O-β-D-xylopyranosyl-D-xylose, all of which were derived by partial hydrolysis of polysaccharides. 2-O-α-L-Arabopyranosyl-glycerol has been synthesized via the Koenigs-Knorr condensation.