Titania-alumina binary oxide supported vanadia catalysts calcined at different temperatures were studied by X-ray diffraction, infrared, oxygen chemisorption and surface area measurements to establish the effects of vanadia loading and thermal treatments on the structure of the dispersed vanadium oxide species. The results suggest that vanadia when calcined at 773 K is in highly dispersed state on the support surface. This dispersion is mostly retained upto a calcination temperature of 873 K. However, thermal treatments above 873 K transform vanadia and titania into crystalline phases and then TiO2 anatase into rutile.