Customs duties are one of the oldest tax forms, and it's payable on all goods which are imported. Customs duties are part of every state's tax system. Customs duties are included in the group of so-called indirect taxes. According to the General Tax Law, customs duties are a form of public duty or financial payment which is paid on import and export. A fundamental feature of the customs system is the control of goods passing through the customs territory. For normal functioning of trade, it is necessary to regulate customs system. The subject of the customs system is the area of economic relations between Croatia and abroad. The customs system is not static and it is necessary to follow technological and political challenges which states come across. For the sake of the possible distance from the world market, it was necessary to make some changes which can allow opening markets of America and many Asian countries. With its accession to the European Union, the Republic of Croatia has introduced many changes to the customs system. Also, Croatia had to adapted the legislation to these changes. The most important change is the abolition of customs duties in the customs territory of the European Union. With it's accession to the European Union, Croatia also had to leave CEFTA. One consequence of Croatia's accession to the EU is a reduction in fiscal revenue from customs duties due to reduced customs protection. Generally, customs policy is one of the foundations of the European Union. Customs policy played a key role in creating an integrated internal market and a common economic policy. It defines the unique obligations in functioninig at the external borders of the Union by creating common rules on flows and customs clearance of goods.