Iodide titanium films have been grown on tungsten substrates by means of a TiI4 flow system. It was found that tungsten diffusion takes place during the titanium film deposition. Tungsten concentrations as high as 14 at.% have been recorded at 1350 °C deposition temperature. On cooling the films to room temperature, titanium remains in the β phase to an extent that depends on the film deposition time. The films were hydrogenated at 500 °C and a large hysteresis effect was observed in the P-X diagram. This hysteresis effect is explained by considering the influence of the tungsten diffusion into the films.