The doctoral thesis deals with the transit of goods, which is a topic belonging to the realm of international economic law. Thus, an economic and legal analysis will be carried out to ascertain how goods in transit affect markets and influence profit and loss, depending on the performance of the abovementioned transit of goods. The right of transit has not gained much attention from international economic law, which is concerned directly with world trade. Consequently, it is very important that this topic is analysed in order to achieve better economic relationships among States within a globalised world. The transit of goods exerts a great influence on foreign trade. In particular, it plays a significant role in relation to the landlocked States, since it has a decisive impact on their economic growth. In this way, the controversy about the existence of a freedom of transit or about the existence of a right of transit will be observed from a legal perspective. This is one of the key concepts that will be developed in the doctoral thesis. It is essential that a clear definition of the right of transit as regards its status in public international law should be developed from the view of customary international law. In addition to a theoretical approximation to the notion of transit, the research also tries to ascertain in a more practical way, the effect on the day-to-day operation of commercial relationships without losing the perspective of public international law. In other words, it tries to find the issues raised by the transit of goods and the positive or negative influence on the markets as a result, while also analysing the economic development of each State. Therefore, the doctoral thesis considers the effect of the difficulties suffered by the goods in transit at the legal level as well as at the bureaucratic level. To that end, the existent case law and their problems relating international customs transit as well as other related issues are analysed. With regard to the case law, it is important to emphasise the recent dispute between the European Union, India and Brazil concerning the seizure of pharmaceutical products in transit in Netherlands in accordance with a European Regulation on intellectual property rights. Nevertheless, there are more cases which have been reported under the dispute settlement mechanism of the World Trade Organisation (WTO), although so far there has been only one case which has been solved before a Panel in 2009 (WT/DS366/R). By virtue of this scientific research, it is expected to bring to light a critical question of international economic law which can revolutionize the contemporary system of world trade.