The pretreatment of soda-anthraquinone (AQ) wheat straw pulp with purified endo-(1, 4)-β-xylanase was studied. Different xylanase dosages (0, 2, 20 and 100 IUg-1) were applied to the pulp before an ECF (Elemental Chlorine Free) bleaching sequence. The fiber characteristics, brightness stability and strength properties of the obtained pulps were determined. The results showed that the fiber characteristics were not significantly affected by the enzyme pretreatment. On the other hand, the xylanase pretreatment lowered the strength properties of the pulp. A slight improvement in lignin removal was observed, thus improving pulp bleachability, the results agreeing with those obtained on wood pulps. Furthermore, higher paper brightness stability was obtained by the xylanase pretreatment, explained by the removal of the metal ions from the pulp samples.