Abstract: Provided are methods for degrading or converting a cellulosic material, comprising: treating the cellulosic material with an enzyme composition in the presence of a polypeptide having catalase activity; and enzyme composition used for degrading or converting a cellulosic material comprising one or more (e.g., several) enzymes having cellulolytic and/or hemicellulolytic activity and a polypeptide having catalase activity.