The physicochemical properties, hydrocarbon type composition, concentration of trace elements, and data on metal porphyrin complexes of crude oils and bitumens from multiage deposits of the West Siberian oil-gas basin were analyzed. Vast published material and analytic studies of the author herself were summarized. In the geochemical characteristics, a substantial difference of Paleozoic oils from younger oils was revealed only in certain tectonic zones, e.g., in the Nyurol' Trough, whereas no differences between the Pre-Jurassic and Mesozoic oils were found in the Khanty-Mansi Trough, Shaimsk raion, or the Middle Ob region. It was shown that crude oils from the overwhelming majority of oil fields of Southeastern West Siberia are syngenetic to reservoir rock deposits and have a characteristic geochemical appearance of their own. The discovery of independent oil-generation centers in Paleozoic deposits in the Nyurol Trough area considerably increases the oil-and-gas prospectivity of this region.