Hydroquinone-alpha-glucoside was synthesised from hydroquinone and maltose as glucosyl donor by transglucosylation in a water system with alpha-glucosidase from baker's yeast. Only one phenolic -OH group was alpha-anomer-selectively glucosylated. The optimum conditions for transglucosylation reaction were at 30 degrees C for 20 h with 50 mM hydroquinone and 1.5 M maltose in 100 mM sodium citrate/phosphate buffer at pH 5.5. The glucoside was obtained at 0.6 mg/ml with a 4.6% molar yield with respect to hydroquinone.