Sulphur dioxide obtained during fuels burning in combustion engines is one of the main pollutants. In diesel oils and gasolines the sulphur content must be 5-10 ppm and in jet fuels -300-3000 ppm. However the production of hydrofined jet fuel is problematic. The reason is deterioration of fuel stability and antioxygenic properties. The oxidative desulphurization of straight-run kerosene was investigated. This method combines oxidation by atmospheric oxygen of sulphur compounds under increased temperature and pressure in the presence of water in the reaction medium, and removal of oxidized sulphur compounds from the oxidation-treated fuel via rectification. It was showed that water partially extracts from the hydrocarbon medium acidic compounds, formed in the beginning stage of oxidation, dissociation of which leads to the formation in water acidic medium. As a result, a pathway of the hydroperoxides decomposition partially changes from the formation of carbonic acids and oxyacids to the formation of alcohols, phenols and alkylphenols, which displayed an inhibitory effect in hydrocarbon oxidation. It was assumed that an inhibitory effect of water, in addition to the creation reverse micelles with peroxides and complexes with free radicals, caused by oxidation products created in the beginning stage of oxidation. The effect of water/kerosene ratio on the oxidative desulphurization of straight-run kerosene fraction has been examined. It was found that water improves process selectivity with insignificant influence on the degree of sulphur recovery. The optimum value of water/kerosene ratio for the fuel containing 0.15% mass of sulphuric compounds has been determined.