Xylanase preparations free of cellulase contamination are often required for applications in the pulp and paper industry. Xylanases from Trichoderma have been purified and characterized in an effort to better understand the behavior of the various components of the xylanolytic system in order to optimize their effect. However, purification and characterization of xylanases from Trichoderma species are still incomplete. This review organizes current techniques for xylanase purification and examines the properties of xylanases that have been previously characterized. Problems with assays, lyophilizing, gel permeation behavior, gel electrophoresis and developing are also noted. From this review, a strategy for the isolation of an endoxylanase from a commercial preparation of T. longibrachiatum is developed.