The article is devoted to one of the aspects of the problem of correlation between international and domestic law, namely the relationship between international and national law. This relationship is developing dynamically. The development of the interconnectedness of international and domestic law occurs in connection with the constant increase in the number of international treaties and national legal acts aimed at regulating social and domestic relations, which is the object of international cooperation. At present, trends in the further development of international law and its interaction with national legal systems have begun to emerge clearly. The process of globalization has strengthened the interconnection of states, expanded the range of intrastate social relations that are a common object of regulation of two legal systems - the international legal system and the domestic legal system. Based on the analysis of the provisions of the general theory of law and the doctrine of international law and international normative acts, the theoretical and legal problems of the relationship between domestic and international law are considered. It explores the social and legal nature of the relationship between the two legal systems and explores the importance of harmonizing domestic state law with international law. It is noted that although international law and domestic law have a single social nature, they functionally act as two relatively independent and closely interacting and interdependent systems of law. The nature of their interrelations, methods and forms of interaction, as well as their functional connection, interdependence and the role of the state in this process are revealed. It is emphasized that the relationship and interaction are not limited only to the norms of the two legal systems, but cover the two legal systems as a whole. Consequently, there must be harmonization of the norms of national law with all sources of international law, including with the individual international obligations of states. The article notes that the state is a participant in the creation of legal norms of both domestic and international law. The process of coordinating the will or position of states when concluding international treaties is regulated by the norms of international law, and the process and procedure for expressing these declarations of will or positions are determined by the norms of national law. At the same time, international law does not belong to the legal system of specific states, although in fact it is part of all legal systems. If the object of regulation coincides, the norms of international law always take precedence over domestic ones. According to the author of the article, the concept of a legal conflict should not be identified with the invalidity of international treaties. It is argued that the case of conflict occurs only with a valid contract. It is also emphasized that many norms, enshrined in international law by treaty or customary means, acquire the character of jus cogens and therefore are binding on all states, regardless of ratification or accession to certain treaties or agreements. The article points out that international law imposes an obligation on the state as a whole, but it is domestic law that determines state bodies and officials who are responsible for fulfilling the international obligations of the state.
 The purpose of the article is to theoretically clarify the essence of the relationship and interaction between international and domestic law, to identify the importance of harmonizing domestic legislation with international law and the grounds for the priority of international norms over national law.