Removing noncellulosic compounds from pulps clearly increased the accessibility of the surfaces of the cellulose fibers to endoglucanases. Thus, increased chain scission upon enzymatic hydrolysis was observed when hemicelluloses were removed from a hardwood kraft pulp by alkaline extraction and xylanase treatment, respectively, and when lignin was removed from a softwood sulfite pulp by elemental chlorine free bleaching. Pulps with increased cellulose II content showed a greater accessibility of cellulose toward endoglucanases because of their increased swelling capacity compared to pulps of native cellulose. Reactivity of sulfite pulps was determined as filterability of the derived viscose samples and was not improved by endoglucanase treatment, whereas this was reported for CCE treated kraft pulps in literature