Bacillus thuringinesis as a Gram-positive bacterium is found in the soil and digestive system of certain butterfly and moth caterpillars. Thanks to its cytological (Cyt), crystalline (Cry), vegetative (Vip) and secreted (Sip) proteins that have insecticidal action on pests, it is most commonly used as a biopesticide. It is proven that B. thuringiensis effects on pest species of the genus Coleoptera, Lepidoptera and Diptera and in certain nematodes. Once B. thuringiensis reaches the larva’s gut it leads to its paralysis and death. With the advancement of technology, various formulations of B. thuringiensis biopreparations containing strains such as B. thuringiensis ssp. aizawai, B. thuringiensis ssp. kurtsaki, B. thuringiensis ssp. tenebrinonis and B. thuringiensis ssp. israelensis are produced on the world market today. Due to the insecticidal action on only certain economically significant pests, B. thuringiensis preparations do not represent damage to the environment and desirable insects. In order to reduce the global losses of fruits and vegetables caused by pests, over time, GM crops that already contain a strain of B. thuringiensis bacteria are increasingly being grown. Although it is said that GM crops do not pose a danger to humans and pollinators, over time it has been shown that such food can cause allergies in humans. They can also lead to resistance of certain insects to this good bacterium which is not the case with B. thuringiensis biopreparations. Therefore, it is safest to use B. thuringiensis insecticides while B. thuringiensis crops need to be investigated in the long term.