One of the factors negatively influencing an assessment of the tax liability is inflation. An increase in prices of goods and services without simultaneous adjustment for inflation of the construction elements sensitive to erosion, or lack of application of an effective corrective mechanism, leads to a gradual reduction in the taxpayer’s ability to pay. This results in a violation of the principle of tax justice, even in a situation where the provisions of tax law are formally correct. The aim of this article is to answer the question whether there are any legal constructs in Poland that protect taxpayers against the negative impact of inflation and, if so, whether they protect them effectively. The article analyses legal regulations contained in the Personal Income Tax Act and the Inheritance and Donation Tax Act which refer to structural elements of taxes expressed as an amount. The research covers the period of over thirty years, i.e. from the beginning of social and economic changes in Poland, characterised by high inflation, to the present day.