The purpose of this study was to characterize bacteriocins produced by Bacillus subtilis 11A isolated from Indonesian native chicken's ileum. Characterization of bacteriocins included antimicrobial activity, the stability to temperature, pH, and storage time. Antimicrobial activity was tested against Escherichia coli FNCC 0091 , Salmonella typhimurium FNCC 0134, and Staphylococcus aureus FNCC 0143. Stability to temperature was tested to 4, 30, 70, 80, 90, 100 o C for an hour and 121 o C for 15 min. Stability to pH was tested to pH 2,