Mixed nickel-manganese oxides with an ilmenite and spinel structure were investigated in order to elucidate the effect of the crystal structure type and cation coordination on the catalytic performance in the reactions of complete oxidation of ethyl acetate, benzene and carbon monoxide. Highly dispersive and well-crystallized monophase oxides with an ilmenite (NiMnO3) and spinel (NixMn3-xO4) structure were synthesized from homogeneous carbonate precursors. It has been shown that the ilmenite-type catalysts were significantly more active for the catalytic reactions studied than the nickel-manganese spinels. However, highly dispersive ilmenite-type oxides are more effective for the complete oxidation of hydrocarbons, whereas NiMnO3 with a good crystallinity was the best catalyst for CO oxidation. The results obtained show that the nickel-manganese oxides with an ilmenite-type structure are perspective catalysts for catalytic neutralization of exhaust gases from organic compounds.