A kinetic study of the enzymatic hydrolysis of two celluloses with different structural features was performed at various temperatures (26–50°C). The enzymatic system consisted of three types of enzymes: E1—β-1,4-glucan glucanohydrolase; E2—β-1,4-glucan cellobiohydrolase; and E3—β-glucosidase. A mathematical model for the mechanism of the hydrolysis of cellulosic materials catalyzed by a multienzymatic system was checked and a good rationalization of the experimental results was achieved. Uncompetitive and competitive glucose inhibition on E1 and E2, respectively, appeared to occur for both substrates. Inhibition by cellobiose was checked at 34°C on one substrate. The Vmax, Km, and glucose inhibition constants were optimized and their dependence on temperature determined.