Confidential cooperation is a separate interdisciplinary legal institution and a separate type of procedural and legal relations between authorized employees of public authorities and individuals who cooperate with them. According to Art. 19 of the Constitution of Ukraine, such relations and the activities of these authorities must be regulated by the laws of Ukraine. However, the institution of confidential cooperation in the legislation is insufficiently regulated, there are no definitions of basic concepts, and the existing provisions of law are contained in various laws and only fragmentarily regulate the relevant legal relations, which complicates their understanding, researching and using. The purpose of the article is a general legal analysis of the institute of confidential cooperation and relevant legal relations; definition of its concepts, principles, subjects, object and content in the context of activity of the National Anti-Corruption Bureau of Ukraine (hereinafter – the National Bureau). Methodology. During the writing of the article general scientific methods were used: systems analysis, analogy and comparison, as well as common law methods: rather-legal method, technical legal method, logical and legal reasoning. The state of scientific research and the current legislation of Ukraine, which regulates the relevant legal relations, have been analyzed, its separate norms have been compared. The basic legal terms on the raised subject have been defined. A systematic analysis of the legal institute and the legal relations of confidential cooperation has been conducted both from a purely doctrinal point of view and on the example of activity of the law enforcement agency. Some features and characteristics of the relevant institution and relations are clarified. The results of the research are generalized, concretized and presented in the form of statements and conclusions. Therefore, they can be used in other scientific researches and have both scientific and practical value. The scientific novelty is that in open sources, confidential cooperation is for the first time systematically considered as a separate legal institution and a type of legal relationship; the conceptual and categorical apparatus, principles, subjects, object and content are determined, in particular the rights, duties, responsibilities and guarantees of both authorized employees and confidants are studied in detail. For the first time, the issue of the functioning of the institute of confidential cooperation in the National Bureau, which has its own features and differences in comparison with other law enforcement agencies, was studied. The results of the study can also be used to raise awareness of practitioners, the legal community and the public on the specified issue, as well as in rule-making. Conclusions: the institution of confidential cooperation should be thoroughly regulated by law, as it is connected with law enforcement activities of state bodies and the risk of violation of constitutional human rights and interests. Legal adjustment of the legal institute and legal relations does not pose a threat to the disclosure of forms and methods of operational search, intelligence and counterintelligence activities. At the same time, it provides legal certainty, as well as guarantees the state’s observance of the principles of legality, supremacy of law, and respect for human rights and freedoms. In general, the relevant legal relations should be regulated within the framework of operational search activity law and fixed in one legislative act – the Law of Ukraine “On Operational Search Activity”, in which the basic concepts, subjects and their rights, duties, responsibilities and guarantees should be defined. At the same time, it is necessary to resolve the conflicts with other rules of law, in particular those governing the institution of whistleblowers