AbstractOxidation resistant intermetallic compounds based on NiAl, TiAl, and MoSi2 are of interest for high temperature applications. Each system exhibits different life-limiting degradation modes due to oxidation. β-NiAl forms protective α-Al2O3 scales. Breakdown follows well-established diffusion controlled processes resulting in survival for thousands of hours. The effect of thermal cycling and spalling is well established. Ti3Al and TiAl compounds form less protective mixed TiO2 and A12O3 scales. However at realistic use temperatures (600°–800 °C), scale growth rates are acceptably low. The critical factor is embrittlement due to interstitial oxygen diffusion over a matter of hours. Solutions based on alloy development and coatings have not been satisfactory. MoSi2 materials exhibit very low oxidation rates at very high temperatures. However, low temperature (500°C) pest oxidation can be a catastrophic transient effect. Material integrity is a key factor. Fracture occurs because of accelerated growth of non-protective mixed MoO2–SiO2 scales in pores and microcracks.