The most important income of every country is taxes. In today’s financial system, it is interesting to note that there is no tax without states, nor is there a state without taxes. The notion of taxes as historical categories is conditioned by economic, political, social, but also numerous other circumstances. Tax is a form of forced giving that appoints the state, is not targeted and has no direct counteraction. One of the most significant taxes today is certainly the income tax. Income tax is often referred to as the “king” among taxes, and is defined as a direct tax, i.e. as a tax that is imposed directly on the income of the person or household that should bear the tax burden. The Republic of Croatia is one of the countries with the most frequent tax changes, so over time, income tax is not exempt from that. The most common changes go in the direction of linking personal deduction and tax rate. The form of income tax is relatively young, and began to appear in the late 1990's when the so-called. "War tax" on net salaries and other personal income. With the special municipal tax, the marginal tax rate was higher than 90% for the highest incomes. The consequence of this system has been tax evasion through a number of tax exemptions and reliefs. Today, income tax has five different sources of taxation and two tax rates, 24% and 36% regardless of the amount of the tax base. Since taxes are a very variable category in Croatia, the latest changes go back to reducing the tax rate to 30% and 20%, respectively, which should occur early next year.