The subject of the conducted research is the development of sanction regulations in light of Polish and EU law. Sanction regulations were innovative elements introduced to the Act of 8 January 1993 on the value added tax and excise duty, which, due to the high budgetary significance of both taxes, became the most important substantive Polish tax law passed in connection with the reform of the Polish tax system. In the course of the analyses, changes in VAT sanction regulations were indicated by considering the subsequent questions: 1. What was the reason for the changes made to these regulations in the period preceding Poland’s accession to the EU? 2. What was the impact of EU law and case law of the EU Court of Justice on Polish sanction regulations before and after Poland's accession to the EU? 3. Were there other reasons for the implemented changes and what did they entail? As a research method, an analysis of normative material, views presented in legal doctrine and in case law of the Constitutional Tribunal (CT) and the EU Court of Justice was adopted. Developmentof VAT sanction regulations in the period preceding Poland’s accession to the EU was caused by the scope and frequency of violations of instrumental tax obligation committed by taxpayers. The second reason for changes in the content of the examined regulations was the influence of case law of the Constitutional Tribunal which sought to designate the limits for the application of tax sanctions. The third factor contributing to the changes in sanction regulations was case law of the EU Court of Justice, which is a crucial part of acquis communautaire.