Among 17 fungal isolates isolated from soil of El-hawia, El-hada, El-kaym and Karwa in Taif governorate in Saudi Arabia, two isolates showed high efficacy in producing cellulases enzymes. They were identified to be Alternaria alternata and Aspergillus wentii. Some factors such as carbon and wheat bran as a raw material, nitrogen, pH and incubation temperature were investigated. Results indicated that glucose and cellulose were the most effective as a carbon source while, urea was the best nitrogen source for cellulases production. Initial pH 5.0 and incubation temperatures at 25 or 35ºC achieved high cellulases production.