Natural gas in accordance with the provisions of the Energy Strategy of Ukraine for the period up to 2035, despite the significant development of "green" energy remains the main energy source in the country. Due to the accession to the single European area of regulation of natural gas trade in the country, all calculations for fuel consumption should be performed in units of energy. Thus, the defining issues are the quality of natural gas. One of the features of the gas supply system is a significant degree of uncertainty in the change of a large number of disturbing factors and constantly changing parameters of its operation. Among others, a mathematical model based on the theory of fuzzy logic was chosen to assess quality. Based on the results of consideration of factors characterizing the physical and chemical properties of natural gas extracted from the field, the quality of its preparation for transportation and technical conditions of operation of the gas distribution system of the settlement, a fuzzy set was obtained to determine fuel quality. One of the methods of analysis in complex and multiconnected systems is the Pareto method, which consists in classifying problems into a few, but essential, and numerous, but insignificant. Modeling the management of natural gas quality using the membership functions of linguistic variables, which are the factors influencing it by the Pareto method, allows to vary the most significant factors that take into account the most influential of them. The resulting Pareto bar chart clearly illustrates the number of factors influencing the quality of natural gas. The diagram shows that the most influential factors on the quality of natural gas and on reducing the operational reliability of gas transmission and gas distribution systems are, respectively, higher heat of combustion under standard conditions and fuel moisture content. In this regard, in the organizational and technological support of natural gas consumption at a high level, they should be considered in the first place.