Results of this study demonstrate that enzymatic pretreatment of pulps enables energy savings in the refining process. Pretreatments of NBSK pulp with 3 different commercial xylanases resulted in a faster increase in the pulp freeness that reduced energy input for refining. The partial xylan removal by these enzymes affected the properties of cellulosic pulp and paper. The tensile properties of paper were improved by pretreatment with a pure xylanase while the additional activity of cellulases in the other two tested enzymes negatively influenced the tear resistance. Only the pure xylanase improved the pulp and paper properties. The results of this study provide evidence that the purity of xylanases used in papermaking is of great importance and may decide of paper quality and production costs.