The purpose of the study is to substantiate methodological approaches for conducting a statistical study of the structure of budget investments and their approbation at the level of the regions of the Russian Federation on the basis of an assessment of data available in official statistical and administrative records on indexes of the composition of budget investments, analyzing scientific papers devoted to the study of the structure of investments, identifying and systematizing signs of gradation of budget investments for development and analysis their complex structure. The methodological proposals formed were the basis for the application of methods of multidimensional statistical analysis of the distribution of the regions of the Russian Federation by indexes of the structure of budget investments to determine territorial differences in the implementation of state investment programs of socio-economic development.Materials and methods. The study used theoretical methods: analysis, synthesis, comparison of sources of information about budget investments, as well as mathematical and statistical research methods: structural and dynamic analysis, descriptive statistics, multidimensional grouping, cluster analysis.Results. Based on the analysis of regulatory and legal documentation, scientific literature on the research topic, author’s publications, a classification of indexes of the structure of budget investments was formed. The structural and dynamic analysis of the index “Investments in fixed assets by sources of financing” (in the total amount of funds, in comparison with budget funds, by levels of budget expenditures of investments in fixed assets: federal budget, funds from the budget of the regions of the Russian Federation, local budget) was carried out for 2005-2009 and 2013-2021. The variability of the share of expenditures from the federal and regional budgets is revealed, which may be related to the implementation of state regulation measures in the redistribution of investment resources at the federal and regional levels. Using the methods of descriptive statistics, multidimensional grouping, clustering, a comprehensive analysis of the statistical distribution of indexes of budget investments by regions for the period 2015-2021 is presented, resulting in four clusters, an assessment of qualitative differences in the structure of budget investments by selected clusters is given.Conclusion. In this paper, a methodological toolkit is proposed for a full-system representation of the composition of budget investments, provided with the capabilities of official statistical and administrative accounting and allowing organizing the totality of indexes of the structure of budget investments by territorial division, by sources of financing, by spending directions. The practical significance of the study consists in a proven assessment of the statistical distribution of indexes of the structure of budget investments by the share of budget investments in the total volume of investments in fixed assets (own and attracted funds), as well as by budget levels (federal, regional and local levels), identified spatial and dynamic changes in the selected cluster groups of the Russian Federation regions. Executive authorities and local self-government bodies in the formation and implementation of budgets in the areas of spending budget investments in order to increase their socio-economic effectiveness can apply the results obtained.