The influence of the SnO₂ surface modification by the SnO₂-Au nanocomposites on conductivity response to such reducing gases as CO and H₂ has been analyzed in the present paper. Both initial SnO₂ films, subjected for surface modification, and SnO₂-Au nanocomposites were deposited by Successive Ionic Layer Deposition (SILD) method. The SnO₂-Au nanocomposites with Au/Sn ratio ∼1 were synthesized using HAuCl₄ and SnCl₂ precursors. The thickness of the Au-SnO₂ nanolayers varied from 0.7-1.0 nm to 10-15 nm. It was established that the increase in the thickness of the SnO₂-Au nanocomposite layer formed on the surface of the SnO₂ films was accompanied by both the improvement of sensor response and the decrease in response and recovery times. An explanation of the observed effects has been proposed.