ENResearch purpose. The EU Customs Law is a significant branch of the EU substantive law. On the basis of the Union Customs Code (UCC; Regulation [EU] No. 952/2013) and the Combined Nomenclature of the European Union (Regulation [EU] No. 2658/87 and its Annexes), it regulates the international trade of the European Union and its Member States with the third countries, in particular the taxation of the international trade operations by applying the customs duties/tariffs. However, after the adoption of the UCC, which imperatively requires all the customs administrations of the EU Member States to work as one, the problem of the uniform application of the EU customs law remains very important. Therefore, the authors analyse the practice of the Baltic States (i.e. Republics of Estonia, Latvia and Lithuania) in this area, based on the case law of the Court of Justice of the European Union (CJEU) in cases involving references to the CJEU by the national courts of different Baltic States. Design/Methodology/Approach. The authors used the thematic analysis method and the method of generalisation of professional (judicial) practice as the basis of the chosen methodology and its design. Therefore, first of all, the authors have selected the judicial cases of the CJEU (in the period from 2010 to 2018) related to a certain theme – customs duties. Second, the authors compared the practice of the CJEU in such cases, which are attributable to the relevant EU Member State in order to identify the problems of uniformity in the application of the EU customs law (specific to the different Baltic States). Finally, by using comparative insights and comparative method, the authors present proposals for the improvement of legal regulation to ensure the compatibility of national rules and practices with the EU law.Findings. During the investigation, the authors established that the problems of the uniform application of the EU customs law in the Baltic States arose in specific areas. Such areas were tariff classification of goods, determination of the origin and value of goods (in the case of Latvia), regulation of customs procedures (in the case of Estonia), customs duties and other import taxes preferences (in the case of Lithuania). At the same time, it was established that the national courts of the Republic of Lithuania were the least active in ensuring co-operation with the CJEU this area, which could have been caused by the improper national legal regulations. Originality/Value/Practical implications. The authors present (after the assessment of the experience of the Baltic States) the proposals for the improvement of both the legal regulations of the EU customs law as well as national legal regulations (in particular – in the Republic of Lithuania) to improve the areas that cause systemic irregularities of the uniform regulation of the international trade regulatory measures of the European Union. Whilst some of the similar studies were completed in the recent years (e.g. Limbach 2015), they do not provide a detailed comparative analysis of the issues that were investigated, specifically considering the situation in the Baltic States. Keywords: international trade; customs duties; Court of Justice of the EU; national courts; Baltic States. [From the publication]