The electrical properties of InP/Au dry contacts and the influence of electrodeposited gold on the electrochemical properties of InP electrodes were studied. From current and impedance measurements on InP/Au dry contacts it is concluded that the chemical composition of an interfacial layer strongly influences the electrical characteristics. Furthermore, interface states are shown to play an important role. The interfacial layer and the interface states also determine to a large extent the electrochemical properties of the gold-plated electrodes.