This contribution deals with the analysis of the impact of changes in the fiscal control institution of entrepreneurs in Poland. The new legislation combined administrative tasks in one institution previously held by the tax and customs administration and fiscal control. Initially, the planned reform of the customs and tax administration was to constitute only the reconstruction of the organizational structure of tax offices, fiscal control offices and customs services. In practice, the newly established National Tax Administration took over the competences of entities appointed on the basis of the previously applicable Act on fiscal control, additionally extending the powers of that body. The National Tax Administration, has gained the extension of existing control powers, which in practice may surprise many taxpayers, forcing them to attach more importance to the documentation of their company than to the development of business potential.