A temperature-programmed reduction study of Cr2O3 samples prepared at 673 and 1073 K in different gaseous media, air or helium, was carried out. It was established that one or two peaks arise from the Cr+3 --> Cr+2 transition for samples treated in air or inert gas, respectively. Results of chemical analysis, X-ray diffraction and adsorption measurements suggest that the different behaviour of the samples as evident from TPR is due to differences in the structural and adsorption features, namely variable degrees of crystallization, crystal defects and different access to the surface. An explanation of the mechanism of reduction is proposed.