Fructosylxyloside (FX) was crystallized from the culture filtrate of Scopulariopsis brevicaulis cultivated in a 300-l fermentor by a series of treatments : clarification by alkaline treatment at 85 degrees C at pH 12; decolorization and deionization by ion exchange resin; separation by column chromatography on MCI gel CK08P; and concentration and crystallization. The crystallization treatment was repeated four times. The average purity of the crystals was 99.7% as a solid base and the yield was 94%. A scaling-up method for the crystallization of FX is proposed. The crystal shape was an octagonal prism and one mole of FX-crystal contained one half mole of water. The specific rotation, [alpha](20)(D) of FX-crystal was +54.1 degrees. The melting point was 111.6 degrees C. The correlation coefficient between the real concentration and that estimated by Brix refractometer was 1.014. The FX-crystals were soluble about 50% more than sucrose at 20-80 degrees C. The sweetness of FX solution was about 30% of that of sucrose solution. The digestibility of FX by the artificial gastric acid was similar to that of sucrose but the hydrolysis rate for FX by alpha-glucosidase was lower than that for sucrose.