Gas-sensing properties of a novel surface functionalized tin oxide material have been studied to demonstrate the possibility of selectivity control by surface state formation. Covalent anchoring of ruthenium oxide on the tin oxide surface (ruthenated tin oxide) is found to give considerable enhancement in sensitivity (320) as well as selectivity to 1000 ppm of liquified petroleum gas (LPG) at 300 °C compared to the sensitivity (4) of pure tin oxide samples. The amount and distribution of grafted ruthenium oxide on the surface of tin oxide seems to be the most important parameter controlling the change in electrical transport with LPG gas adsorption.