For the cathode of Transparent Organic Light Emitting Device (TOLED), ITO film was deposited using RF magnetron sputtering with Cs-vapor introduction during the sputtering process. The work-function of the Cs incorporated ITO film was 4.3 eV with electric conductivity and it was very stable at the atmospheric environment over extended period of time. It was shown that this Cs incorporation technique was effective for the incorporation of Cesium in the ITO film and that it made possible ITO film with low work function