The SnO2-F2O3 thin him sensors with added platinum are studied. The gas-sensing materials (Fe2O3 and SnO2) have been prepared from pentacarbonyl iron [Fe(CO)(5)] and tin tetrachloride (SnCl4) by plasma enhanced chemical vapor deposition method. In order to improve pas-sensing properties, the deposited films are dipped into an aqueous solution of H2PtCl6. 6H(2)O and heat-treated to form the Pt modified SnO2-Fe2O3 thin film sensors. The surface composition of the Pt modified thin films has been studied by means of X-ray photoelectron spectrum. The electrical properties of the prepared sensors and the effect of Pt addition on the gas-sensing characteristics have also been investigated.