Abstract: The oxidation of organic compounds with carbon-carbon double bond with using of molecular oxygen under atmospheric pressure in the presence of polyaniline supported catalyst has been studied. Our purpose was to combine the advantages of supported catalysts and inexpensive oxidant. In our experiments inorganic cobalt(II) salts – cobalt(II) chloride and cobalt(II) acetate – were immobilized on polyaniline matrix. Those catalyst turned out to be efficient and selective for oxidation of unsaturated organic compounds as well as oxidation of hydrocarbons in benzyl position. Oxidation reactions were carried out in relatively mild conditions in presence of molecular oxygen under atmospheric pressure at temperature 333K. Alkenes with terminal carbon-carbon double bonds were selectively oxidized to corresponding epoxides with very high yield and selectivity. Cyclic alkenes were easily oxidized mainly to epoxides. Oxidation of hydrocarbons in benzyl position give ketones as a main products. The yield of the oxidation reaction depends on cobalt compound which was used in polyaniline doping. Due to the fact that amount of cobalt salt immobilized on polyaniline support is critical factor in the oxidation, more detailed comparison of our both catalysts were carried out in testing reaction of dec-1-ene oxidation. In the polymer doping reaction different ratios of cobalt(II) salts and polyaniline were used. Some kind of saturation of polyaniline surface was observed, when concentration of Co(II) reach about 30 mg of Co(II) per gram of sample, after that no further changes were found.