The means (forms), types and aspects of expressing consent by government and international intergovernmental organizations to be bound by a treaty at the universal and regional (European) levels, as well as in the national legal theory and practice of Ukraine have been studied in this thesis. The history of formation, establishment and development of the institute and the stages of expressing consent to be bound by a treaty has been studied. It has been proved that the first means of expressing consent to be bound by a treaty were the oath (swear), the signature of treaties and the exchange of instruments. The peculiarities of ratification formation as the main mean of expressing consent to be bound by a treaty have been examined. The practice of expressing consent to be bound by treaties entered into within the framework of the League of Nations and the United Nations, in particular the emergence of such means as accession and approval, has been studied. Specific features of expressing consent to be bound by a treaty, established in the Vienna Convention on the Law of Treaties 1969, as well as those formulated in the recommendations prepared by the Office of Legal Affairs of the United Nations, in particular the Treaty Handbook 2002 and the Handbook on Final Clauses 2004 have been established. It has been established that international organizations use such means of expressing consent as the approval (UN and its specialized agencies), the signature, and the exchange of instruments (or letters), as well as the ratification in the European Union. The author's definition of the concept of 'expressing consent to be bound by a treaty' is an international act in the form of signature, exchange of instruments constituting a treaty, ratification, acceptance, approval, accession or in any other way agreed by the parties, by which the government expresses its readiness at the international level to assume the legal rights and obligations under a certain treaty. Formation, establishment and development of the institution of expressing consent to be bound by a treaty in the practice of the state agencies of the Ukrainian SSR and Ukraine have been examined. Main existing regulations of Ukraine that regulate the expressing consent to be bound by a treaty have been considered. The powers of the Verkhovna Rada of Ukraine, the President of Ukraine, the Cabinet of Ministers of Ukraine, ministries and other state bodies of Ukraine with regard to expressing consent to be bound by a treaty have been disclosed in detail. The study is based on specific examples of expressing consent to be bound by a treaties concluded on behalf of Ukraine.
