Various used paper materials have been exposed to the action of cellulases from Penicillium funiculosum, Trichoderma reesei, Trichoderma viride and Aspergillus niger. A 2 h incubation period showed cellulase from T. viride the most active except for office paper that was maximally degraded by A. niger cellulase. Cellulase mixtures increased saccharification while sequential treatment with cellulases from T. reesei and P. funiculosum increased biodegradation at values between 15% and 190%. The maximum increase of saccharification (190%) was obtained when T. reesei cellulase initiated the sequential treatment of newspaper relative to the sole action of P. funiculosum cellulase on this non-pretreated and pretreated material.