Some gram-positive bacteria of the genus Bacillus spp. and Clostridium spp. can exist in two alternative states: vegetative and in the form of endospores, which are divided into two types: having an outer shell (exosporium) and not having it. Bacterial controversies have been studied for a long time and yet they remain not fully recognized as objects of the microworld. These resting (dormant) cells, recognized as the most stable form of life on Earth, are formed in the mother cell with a lack of nutrients. The extraordinary resistance of spores to extreme physical and chemical conditions of existence is the main distinguishing feature from vegetative forms, and their life cycle contributes to the wide spread of spore-forming bacteria in various ecosystems. The unique properties of bacterial spores cause increased scientific and medical interest associated with the epidemiological significance of resting cell forms that can be in a metabolically inactive state for tens and hundreds of years. As soon as spores get into human or animal organisms, as well as into canned foods, they germinate and become a source of serious infectious diseases. Spores are an infectious form of spore-forming bacteria, among which the most dangerous are B. anthracis (anthrax causative agent), B. cereus (toxicoinfection), as well as representatives of the genus Clostridium -C. botulinum (botulism), C. perfringens (gas gangrene), and C. difficile (nosocomial infections). The relevance of the research and the prospectiveness of the study of spores mediates the need to disclose their biochemical structure, molecular mechanisms of steadiness, as well as detection and indication using modern analytical tools. The characterized supramolecular structures of endo-and exospores become a target for modern biotechnologies on the principle of "learning from Nature". These biological systems are perspective models for packaging and targeted delivery of enzymes, nucleic acids, antigens and drugs to specific tissues, cells and even intracellular organelles for the treatment of cancerous tumors and the creation of thermostable vaccines. The unique properties of bacterial spores will soon find application in ecosystem technologies as biofungicides and bioinsecticides in