Deduction of VAT supplier factity in the light of the decision-making activity of the CJEU

The topic of tax evasion is still very relevant even at the time of dealing with the lingering economic consequences of the COVID-19 pandemic, at the time of the war in Ukraine and dealing with other associated phenomena, such as high inflation, price increases and others. The fight against tax evasion is often accompanied by the fact that many taxpayers are denied their rights, and often unjustly. More and more, such situations can be encountered in the field of VAT, which is also confirmed by the relatively rich case law of the Court of Justice of the European Union in the given area. The aim of the presented paper is to identify the fundamental problems of VAT deduction in the process of proof in the tax administration, to analyse selected decisions of the Court of Justice of the European Union and to synthesize knowledge applicable to taxpayers in the procedural defence of their rights and interests protected by law. We used several methods of writing scientific papers of this kind in processing the mentioned issue, but mainly analysis, synthesis, and partially also the comparative method, which we applied in mutual contexts.