Purpose. The purpose of this paper was to highlight the results of the study of the influence of the balance of organic carbon in soil and fertilizer systems on the formation of sustainable competitiveness of Ukrainian agricultural enterprises. Methodology / approach. To achieve the purpose, we used such methods: balance (to assess carbon balance in the soil); correlation analysis (to identify and assess the close relationship between the balance of organic carbon in the soil and the Sustainable Competitiveness Index – SCI); econometric modeling (to develop a mathematical model of the dependence of the balance of organic carbon in the soil from the yield of by-products (straw) and the volume of organic fertilizers applied in agricultural enterprises); economic-statistical and monographic (for the assessment and analysis of the influence of the balance of organic carbon in the soil and fertilizer systems on the formation of competitiveness of enterprises); abstract-and-logical (for theoretical generalization and analysis of the research results). The economic database of the 5597 agricultural enterprises located in Ukraine was used as the empirical basis. Results. It was found that one third (33.0 %) of the studied agricultural enterprises of Ukraine had a deficit balance of humus (on average -0.273 t/ha), the rest (67.0 %) had a positive balance of humus, in particular 15.9 % of business entities provided a balance of humus more than 1 t/ha (an average of 1.608 t/ha). This group of enterprises reached an average level of sustainable competitiveness (SCI = 1.296) and was a good example of the formation of competitiveness on the basis of rational land use. The influence of the humus balance on the level of sustainable competitiveness of agricultural enterprises in the markets of three main crops – winter wheat, corn for grain and sunflower – was assessed, which allowed us to identify the industry-specific features of its formation. Originality / scientific novelty. As a result of the study it was identified and quantified, for the first time, the impact of the balance of organic carbon in the soil on the formation of sustainable competitiveness of agricultural enterprises. For the first time, a two-factor linear mathematical model of the dependence of the balance of humus in the soil from the yield of by-products (straw) and the volume of organic fertilizers applied in Ukrainian agricultural enterprises was developed. The provision on the features of the formation of sustainable competitiveness of agricultural enterprises under various fertilizer systems was further developed. Practical value / implications. The main results of the study can be used for (i) rapid assessment, regulation and prediction of the balance of organic carbon in the soil; (ii) identification of reserves for increasing sustainable competitiveness of agricultural enterprises; (ii) improving soil protection policy for regulating the reproduction of organic carbon in the soil.