A potential probiotics bacterial strain, CS90, was isolated from Korean soybean paste (doenjang). The strain CS90 showed antimicrobial activity against food-borne pathogenic bacteria including Salmonella enterica, Salmonella enteritids, Salmonella typhymurium, Bacillus cereus, Listeria ivanovii, Listeria. monocytogenes, Sthaphylococcus aureus, and Sthaphylococcus epidermidis and showed a significant survival rate of 35.7 to 57.8% under the artificial gastric acidic condition (pH 2 to 3). The strain CS90 was classified as Bacillus subtilis based on morphological, physiological, chemotaxonomic features and phylogenetic analysis based on 16S rDNA sequence and designated as B. subtilis CS90. B. subtilis CS90 can be used as a potential probiotics.