The literature pertinent to the steam and water corrosion of high-temperature gas-cooled reactor (HTGR) steam generator materials was reviewed and used to corroborate the expected excellent performance of Incoloy 800 and 2¼ Cr—1 Mo steel. Similarly, available information on HTGR primary coolant-metal compatibility (helium corrosion) was assessed in relation to results obtained in ongoing programs. Quantitative results from these programs were interpreted in terms of a qualitative mechanistic model.