The high temperature oxidation of two B2-Fe40Al Iron Aluminides has been studied in isothermal and cyclic conditions in the range 700°C to 1100°C and compared with a FeCrAlY alloy. One of the aluminides was prepared by mechanical alloying with the addition of an Y 2O 3-dispersion that conferred to it improved mechanical properties. No significative differences in the isothermal oxidation of the aluminides have been observed due to the presence of the Y 2O 3. Both aluminides presented higher oxidation rates than the FeCrAlY alloy at 758° and 858°C but lower rates at 1118°C. The tests carried out under thermal cycling (100 1-hour cycles: 40 minutes at 900°C plus 20 minutes at room temperature) showed that the FeCrAlY alloy presented a lower weight increase than both Iron aluminides. Scanning electron microscopy observations revealed a similar acicular morphology of the thin oxide layer formed on the aluminides. The oxide grown on the FeCrAlY alloy presented nodule formation.