The major ingredients of poultry and animal diets are corn and soybean. In the current study, Bacillus subtilis isolate was used to ferment soybean and corn. Total phenolic content, antioxidant activity, antimicrobial activity and some nutrients of fermented soybean and corn have been investigated. Antioxidant activity and phenolic content of fermented corn and soybean significantly increased after fermentation of soybean while decreased in fermented corn. Fermented soybean and corn exhibited varying degrees of inhibitory activity against eight pathogenic microorganisms. The amount of crude protein and ash percentage of both fermented corn and soybean increased while carbohydrate and oil content decreased during fermentation of both substrates. As a consequence, fermented soybeans should be added to animal feed.