The paper analyzes the Croatian customs system. It is very important for all countries, including the Republic of Croatia, to encourage the export of goods. Exports create various benefits, such as the growing need for job creation, the possibility of increasing state reserves, increasing the competitiveness of countries. It should be noted that in the last year, in 2020, the Republic of Croatia achieved 112 billion kuna interms of total exports. Customs duty means a type of indirect tax on goods that is characterized by crossing the customs border. The purpose of the customs system institute is to enable the functioning of the customs system in an efficient manner. The institutes of the customs system are primarily the customs area, customs goods, customs supervision, and the customs payer. A customs area is a place where various regulations of a certain country are applied, primarily customs regulations. Customs goods are all those goods that are characteristic of being brought into the customs territory. Customs supervision are all those measures aimed at stopping the unauthorized handling of customs goods. A customs payer is a person who has to pay customs duties and all other customs costs. Customs can be observed according to the direction of movement of goods, purpose, subject of decision-making, degree of benefit, effects of customs protection, and balancing of domestic foreign prices. The paper analyzes the entire documentation related to the import, export, and transit of goods.