Two Ti(C,N)-based cermets with Ni and Ni–20Cr metallic binder were oxidized at 800°C and 1000°C for up to 100h in static air, and the oxide scales and the transition layers formed on both the cermets were characterized to evaluate their high temperature oxidation behavior in static air using XRD, SEM and EDS. The oxide scales formed on both the cermets at 800°C and 1000°C were not dense, and were multi-layered, consisting of NiO outerlayer, NiTiO 3 interlayer and TiO 2 -based innerlayer. The transition layers were present between the oxide scales and the substrates with increasing oxidation time, which consisted of Ti-based, Ni-based and Mo-based oxides. Oxidation process of both the cermets was mainly controlled by O inward thermodynamic activity, and oxidation at 1000°C was faster than that at 800°C. However, cermet with Ni–20Cr metallic binder was oxidized slower than cermet with Ni metallic binder, due to the richness of Cr in Ni-based binder phase and the rim phase of Ti(C,N) ceramic grains. Cr was completely oxidized to form Cr 0.17 Mo 0.83 O 2 , and was incompletely oxidized to Cr-rich Ti-based oxides, leading to the decrease of O inward thermodynamic activity.