Bacillus thuringiensis (Bt) is characterized by its ability to synthesize crystal toxins and also able to produce bacteriocins such as thuricin, tochicin, entomocin and bacthuricin. The present work, for the first time, describes the biological activity of bacteriocins from B. thuringiensis subsp. cameroun (Btc). Supernatant which was produced from a liquid culture of Btc had antimicrobial activity against various Bt subspecies, ending up to making a inhibition zone on an agar medium. A significant reduction in antimicrobial activity was observed when the supernatant was exposed to heat at 47~50°C for 15 min. Proteins were separated from the supernatant by a fast protein liquid chromatography (FPLC) given the thermal instability. A group of FPLC fractions had antimicrobial activity against Bt subsp. palmanyolensis, israelensis, 1-3, morrisoni, toguchini and kurstaki and a Bacillus. cereus ATCC21768, ATCC14579 and NRRLB-569. Interestingly, when the supernatant was individually incorporated into the liquid cultures of Bt subsp. israelensis (Bti) and mogi (Btm) with mosquitocidal activity, a vegetative cell growth was observed only in the Btm culture 10 h post-incubation. A possible recovery of vegetative Btm cell growth was observed, compared to a control without the supernatant. These results suggest that Btc produced proteinous antimicrobial substances, one of which may be used as a selection marker to separate Btm after possibly conjugating the two mosquitocidal strains.