Enzymatic hydrolysis of cellulosic biomass requires physical contact of cellulolytic enzymes with cellulose chains before they can be depolymerized. From kinetic point of view, a properly designed mixing can improve the efficiency of enzymes by evenly distributing the enzymes onto the substrate and by promptly removing the inhibiting sugar products from enzyme-substrate complexes. So far, only limited information is available in literature on the effect of mixing on enzymatic hydrolysis. This study sought to better understand this issue using our cellulase enzyme and model as well as real substrates. The influences of mixing on the hydrolysis of different types of substrates were compared. The hydrolysis was also carried out using different types of mixing devices and different mixing schemes. The results will be presented and discussed.