A particularly difficult issue in the study of the institution of responsibility in tax law is the question of the guilt of business entities -taxpayers. Since taxes are one of the financial instruments used to build relationships between economic entities and the state, the study of the issue of taxpayers' guilt is particularly relevant. Taxpayers are slowly adapting to changes in tax legislation that came into effect on January 1, 2021. One of the most discussed and radical novelties is the official legalization of the institution of guilt as a mandatory element of certain tax offenses and, accordingly, a necessary condition for holding taxpayers to financial responsibility. The Supreme Court has repeatedly emphasized that taxpayers exercise reasonable care, although the risks of choosing an unscrupulous counterparty lie with them. However, in practice, a situation often arises when regulatory authorities hold business entities -taxpayers to account for violations of tax legislation, without paying attention to the presence of guilt in the latter's actions or inactions. Thus, the introduction of the legal construction of guilt into the tax legislation of Ukraine significantly increased the quality of the legislative construction of the composition of the tax offense. However, the legal construction of the guilt of each of the mandatory elements of the composition of a tax offense must contain clear criteria of understanding, since the composition of the offense is the basis for bringing a person to financial responsibility.However, in practice, in Ukrainian realities, questions of qualification of the actual act will still arise. In addition, taking into account the stable and clear vector of Ukraine's foreign policy, it is necessary to harmonize the tax law of Ukraine with the law of the European Union, including in the part of the legal structure of the composition of the tax offense and the institution of guilt.