The invention relates to a process for the liquid-phase separation of xylose from a mixture of C5 and C6 sugars comprising at least xylose and glucose, by adsorption of xylose on a zeolitic adsorbent based on FAU-type zeolite crystals having an Si/Al atomic ratio of less than or equal to 1.5 comprising barium, wherein: said mixture is brought into contact with said adsorbent, by liquid chromatography, to obtain a glucose-enriched liquid phase and a xylose-enriched adsorbed phase; on the one hand, said glucose-enriched liquid phase is recovered and said phase adsorbed on said adsorbent is desorbed by means of a desorption solvent in order to recover the xylose on the other hand.