The aim of the paper is to perform an empirical analysis of the compatibility of the Polish personal income tax (PIT) function with the equal absolute sacrifice principle, which is a major principle of a fair division of tax burden. Throughout the empirical analysis, the author uses analytical methods proposed by Fisher (1927) and Young (1990). The Fisher method is based on calculating the variation in individual sacrifice according to an assumed utility function of income. The Young method is based on selecting the isoelastic utility function of income, which makes all taxpayers sacrifice most equally. Subsequently, a new tax function is determined, which guarantees equal absolute sacrifice according to the selected utility function of income, and compared with the actual tax function. The empirical analysis carried out by the author shows that the Polish personal income tax (PIT) function in 1999-2008 provided a good fit with the equal absolute sacrifice principle, while the sacrifice of most taxpayers was equalized according to reasonable utility functions. However, the author identified three groups of taxpayers whose sacrifice was significantly lower than required by the equal absolute sacrifice principle as well as described the time variation in the compatibility of the Polish tax function with the equal absolute sacrifice principle and in the progressivity of this function.