Abstract: An important factor influencing the efficiency of implementation of budget-fiscal policy is the level of public confidence in the government institutions. The concept of tax expenditures, integrated into the budget process since 2014, contributes to increasing transparency of the conducted policy, and as a result, strengthening of public confidence in the government. The article examines the key aspect of application of the concept of tax expenditures in budget process in OECD countries and Russia, indicates methodological problems, and suggests the vectors for improvement of the existing practice. The scientific novelty consist in carrying out a comparative analysis of integration degree of the concept of tax expenditures into the budget process in various countries. The conclusion is made that the main methodological problem of practical implementation of this concept consists in the absence of the uniform approach to definition of the terms “basic tax” and “tax expenditures”, which in many countries despite substantial experience, did not receive legislative consolidation. The authors highlight the following directions for improvement of the national practice: specification of the definitions of “tax breaks” and “tax expenditures”, as well as use of the results of efficiency assessment of tax expenditures for allocation of subsidies to equalization of fiscal capacity of the constituent entities of the Russian Federation.