Among 20 bacterial isolates isolated from the soil of El-hawia, El-hada, El-kaym and Karwa in Taif governorate in Saudi Arabia,two isolates had high efficacy in producing cellulase enzyme. They belonged to genus Bacillus (Bacillus 8 & 17).  Some factors such as carbon source and wheat bran as a raw material, nitrogen source, pH and incubation temperature were investigated. Results indicated that CMC and cellulose were the most effective as they enhanced cellulases production .Sodium nitrate and ammonium chloride were the best nitrogen sources for cellulases production. Initial pH 7.0 was found to be optimal for growth and cellulase production. Incubation temperatures at 25 - 40ºC achieved high cellulases production by the two isolates.