Abstract: The aim of the present study was production of cellulase enzyme using wheat straw as substrate from Chateomium sp. under Solid State Fermentation (SSF) condition. The culture parameters, such as duration of incubation, incubation temperature, pH, carbon and nitrogen sources and additives, were optimized for enhancing cellulase yield. The optimal level of each parameter for maximum cellulase production by the fungus was determined. Results showed that cellulase production was highest with wheat straw containing production medium supplemented with sucrose, malt extract and CaCl2 and the incubation temperature, time and pH were 35°C, 3rd day and 6.5, respectively. The importance of cellulase enzyme in industries cannot be over emphasized. The crude enzyme when purified may serve the importance of this enzyme in both refining and deinking of recycled papers.