This paper reports the production of very high levels of cellulase free xylanase and associated hemicellulases by ail indigenous thermophilic isolate of Thermomyces lanuginosus (D2W3) using solid-state fermentation. Sorghum straw, an inexpensive and abundant source of carbon supported maximal xylanase activity (11,855 units/g dry substrate). Culturing T lanuginosus D,W, on sorghum straw and optimizing other Culture conditions (media types, particle size of carbon source, inoculum level, inoculum age and additives), yielded increased levels of xylanase (39,726 units/g dry substrate). Further optimization of enzyme production was carried out using Box-Behnken design of experiments with three independent variables (inoculum level, glycerol and ammonium sulphate concentrations) which resulted in very high levels of xylanase, 48,000 +/- 1774 units/g dry substrate, and 2.6 +/- 0.2, 13.4 +/- 0.56, 68 +/- 1.7, 1.4 +/- 0.08: 1.2 +/- 0.05 (units/g dry substrate) of beta-xylosidase, alpha-galactosidase, pectinase, P-mannosidase and alpha-L-arabino-furanosidase, respectively. (c) 2005 Elsevier Ltd. All rights reserved.