Spreading of vanadia over TiO2 (anatase) supports of different specific surfaces has been investigated by XRD, XPS and ESR. It has been found that vanadia migration is favoured over well-developed anatase crystal planes. At 723 K spontaneous spreading takes place, controlled by diffusion of vanadium species through the vanadia monolayer. In reducing atmosphere an induction period is observed, possibly initiated by formation of a structurally modified titania surface layer. Amorphous vanadia is postulated as a transient form between crystalline V2O5 and the vanadia monolayer.