The customs system supports the realization of the leading strategic goals of an economy, but also of the social and ecological goals. It is primarily focused on trade and relations of some country with the rest of the world, but it is also responsible for a numberous other affairs. Thisconfirms its complexity and multidimensionality.The national customs system of Croatia is largely determined by the features of the European Union's customs system. That is the result of the acquis communautaire adoption, which is a duty of all Member States. The basic features of customs systems at EU level are the single internal market, free trade, the rule of freedom, and the IT or electronic business.Accession of Croatia to the EU has positively reflected on its customs system, and has improved relations between Croatia and all EU countries. In addition, relations with third countries are regulated by numerous treaties, and progress in that direction is also expected in the future. This will result in the improvement of competitiveness and performance of Croatia at the international level.