The last decade offshore oil and gas has become the main source of growth of the world's hydrocarbon reserves. Special interest to the geological structure of the Russian Arctic Seas comes from very high hydrocarbon potential of their sedimentary basins, which are expected to take a leading role in future world power supply. Geological and geophysical characteristics of the Russian Arctic Sea sedimentary basins allowed to estimate their hydrocarbon potential by comparison with the known world analogues. Due to difficult climatic conditions in Arctic, we consider only the potential resources of giant (more than 500 million barrels of oil equivalent) deposits. With a limited seismic data, data of gravity and magnetic surveys allowed to outline the main regional structures, to ascertain relations of the discovered hydrocarbon fields to the identified structures. Five major gas-condensate and gas fields are still discovered in this region: three (Shtokman, Ludlov, Ledovoe) in the Barents and two (Leningrad and Rusanov) in the Kara Sea. Primarily structure of sedimentary basins of the Russian Arctic Seas was investigated by geophysical methods. One of successful methods of integrated interpretation of geophysical data is a simulation. Simulation is performed based on computer calculations of gravity effects producing by density heterogeneity of lower hemisphere. The following density models of the Earth crust used seismic and geological data related mainly to the basin sedimentary cover, as well as a few data on the deep seismic boundai-ies (Piskarev, 2004). Sites of direct geological observations relate mostly to folded belts and basement rocks in the periphery areas.