This work presents the titanium effect on the oxidation behaviour of chromia-forming alloys at 950degreesC. When the amount of titanium is high enough in the substrate, in situ XRD permit to show that this element reacts with oxygen to form Cr2TiO5. This oxide is quickly transformed into TiO2 during the first hours of oxidation. These oxides contribute to an increase of the mass gain registered. Titanium leads to a doping effect of the chromia layer inducing an increase of the cationic vacancies concentration and chromium diffusion.