The international banking system serves as the institutional basis for the functioning of the global financial markets. Being in the process of continuous development is its characteristic feature. Each international banking institution has its own specificity and structure. The purposes of their creation and the main functions are defined by their statutes, rules, and founding acts. Despite the diversity of the subject maps of the international banking system, they share a common goal – developing cooperation and ensuring the integrity and stabilization of the world economy, regulation of international economic relations, and ensuring the transnational movement of funds. Legal analysis of statutory activities of international regional development banks, and forms of their interaction. The first among the international regional development banks is the European Investment Bank (EIB), which was founded in 1958 by EU Member States. According to the Bank’s Statute, the objectives of the Bank are to develop the common market by investing funds in the development of Member States’ economies. A legal analysis of the EIB’s purpose, function and structure demonstrates that a regional financial institution was established in the European Region, which by its very nature is an international development which serves as a development not only in relation to EU Member States but also to other European countries. Changes in the geopolitical and economic situation in Europe in the late 1980s – early 1990s were one of the reasons for the creation of the European Bank for Reconstruction and Development, a fundamentally new interstate financial structure that had no analogues concerning either its founders or their goals and methods before. The aim was to create a single lending center for both the public and private sectors of the economy: cooperation between different departments of one international organization should be less complicated than cooperation between two international organizations. Having included the word bank in the Preamble to the Agreement, the Contracting Parties stated that they were establishing a multilateral financial institution that would help to achieve these goals, and create a new and unique structure for cooperation in Europe. With a European Development Bank in the European Region, the EIB, Member States have combined the capabilities and finances of an existing development with a new financial institution, which by its legal nature is a development – EBRD. Membership of two international organizations in an international regional development simultaneously is a new thing in the international banking law. In fact, the European Union is a member of the EBRD three times: EU Member States are members of the European Investment Bank and also members of the EBRD.The creation and operation of European development banks is a sample of interaction forms between international regional development banks, and integration processes observed in the international financial system, within which the international law performers solve current problems, in particular in the political and financial spheres.The article is devoted to the legal analysis of the activities of international regional development banks, forms of their interaction. The purpose, goals, functions, structure of regional development banks are investigated. Forms of their interaction are considered