Xylanases catalyze the hydrolysis of the beta-1,4-glycosidic bonds of xylan, which is the second most abundant component of plant cell walls after cellulose. The recombinant xylanase 10B from Thermotoga maritima MSB8 was prepared and crystallized by the sitting-drop vapour-diffusion method using 40 mM zinc acetate, 20 mM MES buffer pH 6.0 and 3% ethanol. Intensity data were collected to 2.5 A resolution at beamline BL26B2 of SPring-8. Preliminary X-ray analysis showed that the crystal belongs to space group P2(1)2(1)2, with unit-cell parameters a = 77.3, b = 80.6, c = 58.2 A and one molecule per asymmetric unit.