The present study was carried out to isolate and screen bacteriocin producing bacteria from the gut of Penaeus monodon. A total of 68 bacterial isolates were isolated and the strains, M1, M2, M3, M4, M5, M6, M7, M8 and M9 showed inherent capacity of controlling the shrimp pathogens which was screened by acid production test and well diffusion method. Based on morphological and biochemical characters, the potent bacteriocin producing isolate was identified as Bacillus pumilus.