In this study we present some results regarding phase and surface thermal stability, with particular reference to the oxidation of an intermetallic alloy with the composition Ti-23Al-10.3Nb-4.5V-0.9Cr (at.%). The isothermal oxidation kinetics were studied by thermogravimetric analysis. From the experimental results we evaluated the parameters of the process. The weight gain curves showed a parabolic trend for time up to 25 h, For longer than 50 h treatments, the kinetics tend to follow a linear trend with the formation of a non-protective surface oxide layer. The microstructure of the oxide scale was investigated with scanning electron microscopy and energy dispersive X-ray analysis and mapping. The identification of the crystalline phases was carried out with X-ray diffraction analysis.