The electrochemical behaviour of Ti and Ti(7)Al4.5V and Ti(5)Al2.5Fe alloys has been studied in Hank's solution and Fusayama-Mayer solution+0.1% F-. The impedance data were fitted using an equivalent circuit, which takes into account the contribution of the space charge layer. The parameters of the oxide film were determined. The influence of the alloying elements is reflected in increasing resistance of the oxide film and in the growth rate. From the data obtained in artificial saliva containing fluoride ions, it has been proved that the alloying elements do not influence the charge transfer reaction. The alloying elements probably enhance the diffusion of the Ti3+ ions, leading to a thicker oxide film.