Pure Fe₂O₃ and Fe₂O₃ doped with either 2.5–7.5 mass% SiO₂, 6.0 mass% MnO₂ and (6.0%MnO₂+7.5%SiO₂) compacts annealed at 1473 K for 6 h were prepared. The different phases were identified by X-ray diffraction (XRD) and their structures were examined by optical and scanning electron microscopes. The magnetic properties were measured with Vibrating Sample Magnetometer (VSM). Total porosity and pore size distribution were determined and their external volume was also measured. Unlike in SiO₂ doped samples where no new phases were detected, manganese ferrite (MnFe₂O₄) was identified in MnO₂-containing samples. Annealed compacts were isothermally reduced with CO at 1073–1373 K and the O₂-weight loss was continuously recorded. It was found that the reduction rate of SiO₂–Fe₂O₃ samples increases at the early stages with SiO₂ mass% due to the increase in their original porosity. At final stages, the rate was retarded due to the formation of hardly reducible fayalite (Fe₂SiO₄). In MnO₂-containing samples, the reduction rate was retarded at initial stages due to the presence of manganese ferrite. At later stages, the formation of fayalite–manganoan [(Fe, Mn)₂SiO₄] greatly hindered the reduction process. A catastrophic swelling (ΔV=405%) was recorded in 6%MnO₂–Fe₂O₃ compacts and was greatly diminished to 55.95% in presence of 7.5% SiO₂ due to the decrease in size and number of metallic iron whiskers and plates. The reduction mechanism of pure and doped samples was predicted from the correlations between reduction kinetics and the microscopic examinations of partially and completely reduced samples.