The production of xylanases by Chaetomium globosum ch.g./5 and Aspergillus niger A.n.33/2/8 in solid-state fermentation was studied. Several media containing combinations of different carbon sources - wheat bran, wheat straw, beet pulp and apple pomace - were tested. Experiments were carried out in laboratory and pilot-plant scales. The best xylanolytic activities from both Ch.g./5 and A.n.33/2/8 were obtained by growth on a medium containing wheat bran (75%), beet pulp (20%) and apple pomace (5%). On this medium Ch.g./5 produced 17.5 and 20.0 XU/ml and A.n.33/2/8 produced 24.0 and 45 XU/ml of the extract (laboratory and pilot-plant scales, respectively).