The powders of nanocrystalline tin dioxide were prepared by two different methods: conventional hydrolysis of SnCl4 in aqueous solution and novel cryosol technique. The microstructure, composition, and electrical properties of the samples were investigated. The sintered pellets obtained by means of the cryosol method are characterized by significantly higher values of electrical resistance as compared to those prepared by conventional technique. A significant effect of the microstructure on the sensing properties of nanocrystalline SnO2 has been found. The sensitivity to H2S of the samples synthesized by cryosol method was shown to be higher than that of the samples obtained by traditional precipitation.