The study is devoted to a comparative analysis of the savings behavior of the population and the importance of bank deposits in the countries of the Union State, as well as the impact of tax regulation on the timing of raising funds in the banking system of the Republic of Belarus. The parameters of the banking system are illustrated, which are similar for Belarus and Russia; for the period from 2014 to 2020, trends in the significance of deposits of individuals in the countries of the Union State were analyzed, the structure of bank deposits of the population in Belarus and Russia was characterized. Two key differences in attracting funds from the population to bank deposits in the countries of the Union State are highlighted: a higher share of deposits of individuals in national currency in Russia and a higher share of deposits of individuals attracted for a period of more than one year in Belarus. It is shown that the procedure for taxation of personal income on bank deposits in the Republic of Belarus resulted in a significant increase in long-term deposits. The results of this study are of interest for assessing the possibilities of using tools for tax regulation of household savings in the Russian Federation.