Six different agro-industrial waste residues (rice straw, rice bran, corn flakes, wheat bran, wheat flakes, and grinded wheat kernel) were procured from the local market. These substrates (10 g) were moistened (1:1) with different moistening agents (distilled water, tap water, mineral salts solution (FeSO4.7H2O 0.02, MgSO4.7H2O 1.0, (NH4)2SO4 4.0, KH2PO4 0.6, K2HPO4 1.4 mg/gds at pH 5), 0.1 N HCl, sodium acetate buffer (pH 5.5), sodium phosphate buffer pH 7.5) and screened for the production of 1,4-α- D-glucan glucohydrolase for 96 hours in static cultures. The substrate and moistening agent that gave maximum enzyme production were selected and their fermentation conditions were further optimized. The levels of selected solid substrate, moistening agent and fermentation conditions such as pH, temperature, time of incubation, inoculum size etc. were optimized by one variable at a time method. Aspergillus oryzae IIB-6 was found to be a good producer of 1,4-α-D-glucan glucohydrolase in wheat bran medium containing mineral salts as an additional trace elements so that it can be used for biotechnological purposes.