The article is aimed at determining the place of financial law institutions in the fight against such a threat to the economic security of the state, society, and the individual as the shadow economy. A significant number of publications by both domestic and foreign scientists are devoted to this phenomenon. Special attention is paid to reduction methods. However, for many scientific studies, an approach is typical, which boils down to listing, sometimes disclosing, specific ways and techniques of detenevization of the economy without taking into account its "natural" connection with such institutions of financial law as taxation, financial control, monetary regulation and others. It is obvious that, individually and collectively, these institutions can become an impulse for both the growth and suppression of shadow economic activity. In view of this, the purpose of the study is to substantiate the objective need to modify the institutions of financial law in order to reduce shadow economic phenomena. The set of research methods used by the author of the article is represented by two groups: general scientific and private scientific. The first of them includes: analysis, synthesis, induction, deduction. Based on them, the relationship between the categories "economic security", "shadow economy", "public and private finance" has been established. The second one includes absolute and relative statistical values, on the basis of which the processes taking place in the field of finance are characterized. The result of the study was to clarify the place of financial law institutions in the mechanism of countering shadow economic phenomena. Among them, a special place is given to the taxation system, which carries both the causes of shadowization and the potential to reduce the volume of "informal" economic activity by reducing the fiscal burden on business entities and individuals. The emphasis is also placed on monetary regulation tools used to track the financial flows of microactors, including those typical for the shadow environment. The above approach to the application of financial law institutions makes it possible to expand the tools for leveling shadow economic phenomena. In addition, the implementation of the formulated recommendations will have a positive impact on the state of the financial system of the state as a whole and its individual links in particular.