Background . The article is devoted to the development and testing of a method for quantitatively assessing the level of territorial division of labor using the coefficient of regional specialization. Materials and methods . The study is based on the methodological developments of domestic and foreign authors in the field of territorial division of labor, official statistics on the development of manufacturing industries in Russia, the USA and Finland. Results. The authors have developed and tested a method for quantifying the general specialization of a region, showing how diversified the economy of a particular region or country is. Conclusions. It is concluded that the proposed coefficient has such advantages as simplicity of calculation, the ability to compare the levels of territorial division of labor in different countries, the possibility of historical analysis of trends in specialization, and most importantly, using the proposed coefficient, it becomes possible to assess the specialization of the region as a whole. The disadvantage of this approach is that it does not take into account the extreme internal heterogeneity of countries and their regions.