Nanosized iron(III) oxide with an average particle size of 8-10 nm has been synthesized by the thermolysis of iron(III) acetylacetonate using diphenyl ether as a dispersion medium. Reduction processes in a hydrogen atmosphere in the presence of nanosized iron oxide and natural mineral hematite (Fe2O3) have been studied by the temperature-programmed reduction method. The activation energies of the reduction processes have been determined by the Kissinger method; it has been shown that, in the case of nano-Fe2O3, the activation energies are several times higher than the respective values observed for hematite. The adsorption properties of nano-Fe2O3 and hematite have been studied; the isosteric heats of chemisorption of hydrogen and carbon monoxide on the surface of these samples have been determined.