Abstract: Fermentation studies were carried out to investigate the effect of fermentation period, substrate level and micronutrients on the production of endoglucanase by Arachniotus sp. Maximum enzyme activity (1.13 b IU/mL/min) was recorded, when the fungus was cultured in the medium containing 7.5 per cent corn stover as substrate along with 0.2 per cent (NH4)2SO4, 0.05 per cent CaCl2, 2H2O, 0.01 per cent MgSO4.7H2O and 0.2 per cent KH2PO4 under continuos shake conditions at pH 4 and 30±2°C for 24 hours. Addition of inorganic nutrients like (NH4)2SO4, CaC12.2H2O, MgSO2.7H20 and KH2PO4 enhanced the fungal growth and endoglucanase production upto certain (optimum) levels and further higher concentrations had negative effect on enzyme production.