Aim. To substantiate the method of estimating the entropy of the sectoral structure of the economy and on this basis to develop methods of analyzing its sectoral development.Objectives. To define the essence of sectoral entropy of socio-economic systems; to consider the approaches to its assessment and the relationship between the entropy of industries and average per capita gross domestic product (GDP) with the structure of value added of industries of the economy.Methods. To achieve the set goals, the general scientific methods of analysis, synthesis, comparison, generalization, as well as methods of statistical data processing were applied.Results. The expediency of using a probabilistic approach to the estimation of entropy of homogeneous economic structures, which with their development changes according to the exponential law, is substantiated. The position that it is reasonable to estimate the entropy of a homogeneous structure by the averaged sum of entropies of its elements has been argued. The boundary values of the entropy of a homogeneous structure are established. The exponential relationship between the entropy of industries and average GDP per capita and the structure of value added of industries, industry entropy and the share of net taxes on production and imports in the GDP structure has been determined.Conclusions. The identified features of sectoral development of the economy constitute a theoretical and methodological basis, which allows us to establish the significance of influencing factors. This is necessary for sectoral regulation of the economy.