Sorption of Penicillium cellulase onto cotton linters samples differing in physical structure and onto KLASON- lignin from spruce has been investigated by determining cellobiase, CMCL- and ‘linters-activity’ as well as protein content of a cellulase culture filtrate before and after contact with the sorbent at different temperature for different time intervals. CMCL- and cellobiase-activity were found to be reduced much less by the sorption process onto the cellulose samples than ‘linters-activity’ and protein content. Sorption increased in the order: untreated linters < mercerized linters < wet fibrillated (‘colloidal milled’) linters. With the KLASON-lignin also a considerable sorption of the cellulase system was observed. Results are discussed with respect to preferential sorption of enzyme components.