Relevance. In recent years, the Russian economy has faced the global challenges posed by the COVID-19 pandemic and unprecedented sanctions. Understanding how the tax systems of Russian regions respond to these external shocks is crucial for identifying critical stress sources affecting budgets at various levels.Research objective. This study aims to assess and compare tax revenue stress across the federal districts of the Russian Federation, considering different levels of the budget system, and to identify the underlying sources of this stress.Data and methods. The study relies on official data from the Federal Tax Service of the Russian Federation on tax revenues to federal and regional budgets in the federal districts. The analysis covers monthly data from January 2013 to December 2022. The stress index was calculated by measuring the difference between the moving standard deviation and the mean of the annual tax revenue growth rate, with a lag of 1 month. The methodology for decomposing the sources of tax revenue stress was also tested.Results. Over-time assessments of stress indices for tax revenues to federal and regional budgets were obtained for the Russian Federation and its federal districts. The varying levels, dynamics, and budgetary distribution of tax revenue stress across federal districts are explained by differences in the structure, growth rates, and volatility of various taxes, as well as their correlations in these districts. Decomposition of federal and regional tax stress showed the unique role of mineral extraction tax and profit tax as stress amplifiers during crises, while in stable periods, they contribute significantly to stress reduction. The study also establishes the distinct roles of federal districts in intensifying or alleviating overall tax revenue stress during pandemic and sanctions shocks, as well as periods of relative stability.Conclusions. This research demonstrates the importance of assessing and identifying sources of tax revenue stress in regions. Such insights help identify vulnerabilities and reserves for enhancing the resilience of regional and federal budgets through the diversification of regional economic systems and adjustments to tax system rules in response to changing external conditions.