The increasing demand for sustainable waste management strategies has highlighted the potential of Black Soldier Fly Larvae (BSFL), Hermetia illucens, as biological agents for organic waste conversion. This study evaluated the effects of BSFL-mediated bioconversion on the culturable bacterial composition of sheep, pig, and chicken manure under ambient indoor rearing conditions. Seven treatments consisting of different manure combinations with and without BSFL were established and replicated four times. Before treatment, parasitological examination detected Heterakis spp. eggs in chicken manure at 100 eggs per gram (EPG), whereas no parasitic ova were detected in pig and sheep manure samples. Following bioconversion, bacterial isolates were identified using the VITEK® 2 Compact Microbial Identification System. Results revealed shifts in culturable bacterial communities among treatments. Untreated control treatments were dominated by Bacillus species, whereas BSFL-amended substrates contained additional bacterial genera, including Brevibacillus, Lysinibacillus, and Pediococcus. Treatments containing mixed manure substrates and BSFL exhibited greater bacterial richness, with Treatments 5 and 6 recording the highest number of detected bacterial taxa. Treatment 7 was distinguished by the presence of Pediococcus pentosaceus, a bacterium previously associated with compost stabilization and microbial antagonism. Several bacterial taxa reported in the literature to possess agronomic and biological control potential, including Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus thuringiensis, and Lysinibacillus sphaericus, were also identified. The findings suggest that BSFL bioconversion influences the composition of culturable bacterial communities in livestock manure and may contribute to the development of microbiologically enriched organic amendments. Further studies employing molecular techniques and quantitative microbial analyses are recommended to verify microbial abundance, diversity, and functional activity.