Sparse data have hindered efforts to characterize the general geology and petroleum systems in the Siberian Arctic in and east of the Laptev Sea, a region whose potential has often been discounted. Recent acquisition and interpretation of 13,000+ line-km of new long offset, long record reflection data in the North Chukchi, East Siberian, and Laptev Seas has clarified the geometry and inter-relationships of several basins in this enormous 3 × 106 km² area devoid of wells. The 16 sec (PSTM) and 40 km (PSDM) data image a number of attractive late Mesozoic and Cenozoic extensional basins superimposed on older Phanerozoic fold belts that lie below acoustic basement. These basins all relate in various ways to the opening of the Arctic Ocean, and many contain 7.5 to 10 km of sedimentary fill and, up to 20 km in the case of the North Chukchi Basin. A variety of stratigraphic fill styles related to their underlying tectonics can be observed. For example, late-stage (postrift) architecture in the North Chukchi Basin shows Tertiary deltaic sequences traversing over 400 km northward overlying Late Cretaceous rift-fill sediments which contain potential source rocks. In contrast, the Laptev Sea exhibits successions related to a passive margin subsidence history, with low-angle sedimentary systems tracts including well-developed ancient shelf margins and lowstand systems, all cut by intra-continental extensional structures on trend with the active Gakkel Ridge spreading center. Slightly older sediment fill occupies rifts under the East Siberian Sea. The observed potential petroleum systems in this region offer source, reservoir and seal lithologies and hydrocarbon migration geometries to access shelf margin, lowstand depositional systems in addition to the potential within the Neogene rifts.