Aim. B. thuringiensis (Bt) are gram-positive spore-forming aerobic or facultative anaerobic bacteria able to form during sporulation species specific crystal-like inclusions of protein nature, consisting of particular thermolabile endotoxins. Serological Bt variants produce different entomotoxins; their synthesis in many respects depends on the conditions of cultivation. There was accumulated a vast information on the entomotoxins, their origin, synthesis, structure, toxic properties and mechanisms of action on insects. These bacteria are dominating in the microbiomethods of pest control in plants and animals. There are more than 70 serovariants of Bt selectively specific to the definite groups of host insects. However, the description of new variants not always looks justified considering the phylogenetic systematization based on phenotype signs. Methods. A comparative phylogenetic analysis of the Bt intraspecific interrelations was performed on the basis of the cloned 16S rRNA genes of entomopathogenic bacteria BtH₁, BtH₁₀, BtH₁₄. Results. The phylogenetically homogeneous lines were investigated – a homology of 16S rRNA of the strains 1 and 10 ranged from 90,0 to 94,0 %; no distinct genetic isolation among the strains of 14^th and 10^th serovars was revealed. Conclusions. The comparison of nucleotides sequences of 16S rRNA has shown the existence of strains polymorphism within the group of entomopathogens BtH₁, BtH₁₀, BtH₁₄, connected with their entomocide activity.