The paper investigates physico-chemical properties, hydrocarbon composition and product quality of a number of naphthenic oils of Siberia. It is shown that kerosene-gas-oil distillates of the West Siberian oils have low freezing temperature and can be used for winter diesel fuels base and arctic fuels as well. High concentrations of the adamantanoids in the heavily biodegraded oils allow us to consider them as components for production of high density jet fuels.