The results of investigation into some properties of thin SnO2 films aimed at the development of sensitive elements for an analysis of carbon monoxide and hydrocarbons are presented in this paper. The production technology and temperature dependence of film conductivity have been studied. It has been shown that combination of volume doping with silver and surface doping with platinum of the films produced by cathode sputtering allows one to decrease the working temperature of sensors and to extend the range of the measurable values of the concentration of investigated gases. The design of a small–size CO analyzer is described.