Thermogravimetric analysis (TGA) of magnetite (Fe3O4) oxidation was conducted at temperatures ranging from 750 to 900 degrees C over 10 oxidation cycles. Oxidation experiments were carried out in a continuous stream of air for period of 30 min. The oxidized magnetite (Fe3O4), which resulted in formation of hematite (Fe2O3), was then reduced by using continuous stream of CO (5% and 10%) with N-2 balance. The rate of oxidation was determined by the oxygen weight gain. Analysis of the data indicated that the oxidation behavior followed a two-stage process. The initial oxidation, which was very fast, took place in 2 min and was described using nucleation and growth processes with a low activation energy of about 4.21 +/- 0.45 kJ/mol. As the reaction developed within the surface, oxygen transport through the product layer become the rate-controlling step with activation energy of 53.58 +/- 3.56 kJ/mol.