Abstract: Nanosized tin oxide powders were obtained by microwave procedure for their application on gas sensors. Microwave treatment with a wavelength of 2.45GHz produces nanocrystalline powder whose sensing properties are determined by the solvent used during the synthesis process. The gas sensitivity measurements showed that the new aqueous route is better in terms of sensitivity as well as response/recovery time. The microwave assisted heating was found to be a convenient and efficient means of sol gelation and was found to improve the gas sensitivity of the powder as compared to the powder prepared in organic medium. [Copyright &y& Elsevier]