<span>The impossibility of fulfilling tax obligations may have many causes, but nowadays the importance of potential impossibility increases significantly due to the historically unprecedented dependence of the tax system on factors of technical and IT nature. The author, for the purposes of tax law, adapts various types of impossibility of performance established in civil law. He also finds it acceptable to use the concept of impossibility both in relation to the obligation to pay a tax and in relation to the so-called instrumental tax obligations. He discusses the ways in which cases where tax obligations could not be fulfilled have been dealt with to date, taking into account both the jurisprudential concepts of the Polish administrative courts based on the principle of impossibilium nulla obligatio est and the legislative solutions introduced in Ukraine in connection with the 2022 invasion by the Russian Federation, in Poland in connection with the war started in 1939 by the German Third Reich, as well as the regulations introduced into the legal systems of various countries in connection with the COVID-19 pandemic and the new regulations on the Polish National Electronic Invoice System enacted on 16 June 2023. In addition, the author analyses the possibility of using, in the scope discussed, the provisions of the present Tax Ordinance on reliefs in payment of tax obligations. The study indicates the need to introduce general provisions on the impossibility of fulfilling tax obligations. In the author’s opinion, these should address cases of impossibility differently depending on their nature and whether they relate to obligations to pay tax or to instrumental tax obligations.</span>