Abstract. The problems connected with the World Ocean space and ocean resources development, including the Arctic region, have always been at priority level amongst the IMEMO research. The article shows which subjects related to the Arctic region were most demanded at the Institute, and why different forecasts of previous years have not lost their importance and relevance up to the present time. The first part of the research deals with theoretical questions that characterize the legal regime of the Arctic which is based on the broad legal platform, including the 1982 UN Law of the Sea Convention, customary international law norms and provision, as well as national legislation of Arctic states. It means that the legal status of the Arctic Ocean was formed long before the 1982 Convention adoption under the predominant role of customary law, historical legal foundations, Russian and Canadian juridical practice (as of countries with the longest Arctic coastline). Principal differences between the Arctic Ocean and other maritime regions, such as Atlantic, Indian and Pacific Oceans, due to its geographical isolationism, shallow character, the longest shelf zone, special climate conditions, including the presence of ice and special environmental vulnerability, are considered. All attempts to extend different concepts of public domain or world heritage, or even common heritage of mankind to the Arctic Ocean should be declared as speculative and completely incorrect. The common heritage of mankind concept can be applied exclusively to the resources of the seabed and subsoil beyond areas of national jurisdiction of coastal states. So, speaking about the Arctic, this concept can be applied only to the International seabed area (ISA) resources, but only if ISA would be formed here by the Arctic states. The common heritage of mankind status cannot be applied to water spaces, including the Arctic Ocean. In accordance with the 1982 Convention, the waters covering the International Seabed Area are always High Sea, without any exceptions. The legal background of internal historical wares status application to some Russian Arctic seas is analyzed. The main problem here consists in the absence of definite criteria for this kind of qualification in the 1982 Law of the Sea Convention. However, years after the UNCLOS was signed, the practice of states went on the way to expand the number of exceptions as for the bays considered as historic waters. Previously, it could be done only for the bays with the entrance width no more than 24 miles (or two maximum width of the territorial sea), but then all claims have become associated with bays with wide entrance, often very much higher than 24 miles. In addition, historical claims started to be raised not only in respect of bays, but also of small seas, by geographical characters very similar to bays. In the international legal doctrine, three main criteria for the lawful establishment of the historic waters regime, recognized by all, were formed under the following conditions: special geographical location of the waters (especially – away from international shipping lanes); special security and economic interests of the coastal state (the value of the water region and its resources for the economy of a country’s coastal part, or even for the whole country); the subjective intention of the coastal state to seek approval for a historic title under a silent recognition of the actual ownership by other states, and, more or less prolonged, continuous and peaceful (not interrupted) exercise of power (or sovereignty). Taking all these circumstances into account, and that the establishment of the international maritime law rules relating to historic waters went mainly towards the development of customary, not treaty norms, some coastal states, including the USSR, applied this legal status to different maritime regions, in particular Arctic seas and straits. The last topic is connected with the legitimacy of semi-enclosed sea status applicability to the whole Arctic region. Given the fact that a large part of the Arctic Ocean, except its central part with the High Seas legal status, is an area of the Arctic states’ sovereignty and jurisdiction, and that the non-regional states’ entrance to the Arctic is connected with crossing of these waters both from Northern Atlantic and Northern Pacific, it seems possible to extend the Convention’s semi-enclosed status to the whole Arctic Ocean. However, the discussion about the Arctic Ocean identification as an enclosed or semi-enclosed sea, comparable with the Baltic and the Mediterranean, is still in process. This proposal has its supporters and opponents, especially from non-regional countries – particularly China. Meanwhile, the revival of the “Arctic Mediterranean” concept in recent years which characterizes a possible governance regime in the Arctic leads to the top level of the Arctic states’ interest consideration. Finally, the protection of Russia’s national interests in the Arctic region should be successive in character and based on experience and scientific developments that have been achieved in previous years in the framework of IMEMO.