Abstract: In field experiments (2019-2020), the effect of pre-planting treatment with biofertilizers on the complex effect of associative rhizobacteria - growth stimulants on potato tubers was determined. The research was conducted in collaboration with the Institute of Microbiology of the Academy of Sciences of the Republic of Uzbekistan on the basis of soilclimatic zone of Khorezm region, nitrogen-fixing microorganisms in saline soils. The experiments used bacteria isolated from different soils and the rhizosphere of plants, as well as associative nitrogen fixative preparations based on growth stimulants. To determine the effectiveness of bacterization, the tubers were also treated with a chemical agent. The number of microorganisms was determined by traditional methods in solid nutrient conditions. The effectiveness of biopreparations varies depending on the type of genotype, the form of the biopreparation, the activity of nitrogen-fixing microorganisms and external conditions. The highest impact was observed in the Black Prince variety of potato with Earth ointment (Azotobacter chrocoocum), followed by Bist (Pseudomonas putida), Zamin-M (Bacillus subtilis, Bacillus megaterium and Pseudomonas stutzeri). The rate of root formation increased by 1.7-6.9%, under the influence of biological fertilizers, the number of microorganisms in the rhizosphere of potatoes increased by 45-93% compared to the control.