Based on the study of individual elements of the legal mechanism of tax control, it was established that tax control is an effective mechanism of state management of budget revenues in the financial system of Ukraine in the conditions of modern challenges. Currently, in the legislation of our state, the main form of tax control is a tax audit, which is the most effective method of identifying and ensuring payment of undeclared, not assessed and thus not included into budget taxes and is provided by comparing tax declarations (calculations) submitted by taxpayers, with actual data on their financial and economic activity. Proposals for improving the procedure for carrying out documentary checks by introducing amendments to the Tax Code of Ukraine and local regulations of the State Tax Service of Ukraine with a view to regulating tax legal relations and ensuring equality of taxpayers and state bodies in the process of verification are provided in modern conditions of complex challenges for the Ukrainian economy and society.