The study of conducting polymers (CPs) is of high current interest due to their incorporation in a range of applications, including optical and electronic devices. Poly(3,4- Ethylenedioxythiophene)-Poly(Styrene Sulphonate) (PEDOT:PSS) is considered one of the most electrochemically and thermally stable CPs currently available. In many applications there is a requirement for electrical contact to be made between an organic PEDOT:PSS layer and a metallic substrate. Therefore, an understanding of the interaction between the CP and various metals, in order to gauge the long term stability of the metal-CP interface, is of high importance. An in-situ scanning Kelvin probe (SKP) has been employed to measure the Volta potential differences of various PEDOT:PSS coated metal surfaces to identify instances where a reaction may be taking place at the interface. A redox potential of ca. - 0.15 V vs. SHE has been shown where PEDOT:PSS is present in both oxidized and reduced form on the metal surfaces.