Income from self-employment is one of the sources of tax revenue of every state. Tax is a form of forced giving imposed by the state. Due to frequent changes and misunderstanding by most people, taxes are often the subject of various debates. The tax system of the Republic of Croatia is extremely complex, and this text will deal with only one segment of the same tax system, and it is a tax on income from self-employment. Taxes are regulated in a way that they are regulated by laws and special regulations that must be harmonized with the guidelines of the European Union. The aim of this text is to elaborate in detail the tax system and to present the procedures for calculating and paying salaries. Finally, all characteristics and specifics will be processed, as well as the form of income tax prescribed by the tax administration, which is filled in according to precisely defined rules.