Abstract
The article covers the issues of application of customary international law (hereinafter - the CIL) norms within the law of the European Union (hereinafter - the EU). The Court of Justice of the European Union (hereinafter - the CJEU), as many other international judicial organizations, apply CIL norms in its jurisprudence. However, the application mechanism is accompanied by some challenges because of the very nature of the European Community. Since the EU is comprised from various national jurisdictions, also because of the existence of the supranational jurisdictional European institutions, the direct applicability of mentioned CIL norms are troublesome. For more detailed analysis of abovementioned issues, the author briefly analyzes the role and the place of CIL norms within the law of the EU law. Also, there is an attempt to answer to the question of why in some cases CJEU recognizes the legal power of CIL norms and in others not? Does the CJEU follow the recognized formula on establishing the normativity of customary rules such as the requirement of subjective and objective elements? Thus, the given article analyze different approaches and principles of application of CIL norms by relying on existing practice of CJEU. Also, article gives some examples on interaction between EU law and EU obligations towards third states in light of the CIL and ways in which international custom can be invoked by private parties in order to review the legality of EU secondary law. As an outcome of the research, the author reveals his own overview.