The paper considers the issue of whether the production structure of the regional food industry conforms with the conditions of the external environment, the challenges of the processes of globalization and the replacement of technological structures. The main external threats for the food industry enterprises of the region and the most serious and probable opportunities, the prerequisites for the development of enterprises in the current conditions of the external environment are discussed. The meaning of the concept of the rationality of the structure of the regional food industry is interpreted as the term containing the word «rationality» in the sense of a close to limited rationality. It is proposed to determine the degree of rationality in the structure of the regional food industry by the level of conformity of its products to the existing formed demand of consumers, the ability to achieve planned or set goals with the least time and resources, and the degree of conformity of technologies and equipment used in the food industry to the current world trends and technological order. A number of working criteria for the rationality of the structure of the regional food industry are identified, according to which quantitative estimates characterizing the main aspects of the rationality of the structure can be formed. A methodology for quantitative assessment of the degree of rationality in the structure of the regional food industry has been developed, in which a set of relative and integrated indicators characterizing the performance of the selected operational criteria for rationality has been developed and a quantitative assessment algorithm has been proposed that uses statistical data and expert evaluation results. When forming an integral indicator, we use weighting coefficients calculated on the basis of expert estimates processed by the hierarchy analysis method. The results of estimating the degree of rationality of the structure of the food-processing industry of the Primorye Territory, which was carried out on the basis of the developed technique, are presented. The results of testing and verification of the methodology for quantitative evaluation of the rationality of the structure of the regional food industry have shown that this tool allows to fairly objectively assess the degree of rationality of the structure and perform comparative analysis in dynamics, observing one object over a number of years and in static, comparing the rationality level of the regional food industry structure with respect to other similar objects. The developed methodical approach can be used to create a toolkit for quantitative assessment of the rationality of the structure and other interindustry complexes.