ABSTRACT In this work, two catalysts were produced to be used in hydrolysis of cellulose reactions to obtain glucose, a raw material used in the production of bioethanol. The heteropoly acid, H3PW12O40 (HPW), reported as strong and thermally stable acid, was supported on activated carbon (AC) in a ratio varying from 1:1 to 2:1 to produce the catalysts AC-HPW (1:1) and AC-HPW (2:1). The catalysts were tested in cellulose hydrolysis evaluating some reaction variables and the results show the remarkable dependence of reaction temperature, amount and acidity of the catalyst. The results indicate the advantage of supporting HPW on carbonaceous material for using as catalyst in hydrolysis of cellulose, showing better conversion rate into sugars comparing with unsupported HPW.