Introduction. An important component of the soil is microflora, as the soil is not chemical or material substance, so it is biological and biochemical system. Soil microflora has a huge impact on fertility. For the modification of its composition and the growth of beneficial microorganisms, a variety of fertilizers, crop rotation, biologically active substances, etc are used. The number and activity of the soil microflora is also strongly influenced by organo-mineral fertilizers. Activating soil microflora and participating in processes of the involvement of nutrients to it, organo-mineral fertilizers are a great supporter of the biological activity of the soil and the source of energy. At the same time they accelerate humification, enriching the soil with humus and increasing the population of beneficial microorganisms. Objective: to study the effect of organomineral fertilizer on the micromycete composition of the soil and determine the place of phytopathogenic fungi in it. Materials and methods. The studies were conducted by model experience, the object of study – the soil of a barley field and organo-mineral fertilizer – ekoorganika, introduced into it according to the scheme. The results of the discussion. Soil microflora is actively involved in the modification of organic matter and has the greatest impact on its phytosanitary status and fertility. The proportion of phytopathogenic micromycetes inhabiting the soil of the barley fields amounted to 21.4 %, with a predominance of representatives of the genus Fusarium, saprotrophs – 53.7 %, and antagonists – 24.9 %. The numerical and species composition of micromycete populations, depending on the application of organo-mineral fertilizer showed changes in the number of micromycete fungi and significantly affected the fertility of the soil. Conclusion. When organo-mineral fertilizer (ekoorganika) is introduced into the soil, the growth of phytopathogenic microorganisms decreases 3 times and the number of antagonists Trichoderma lignorum increases 4 times.