The influence of Cu doping on electrophysical, structural and gas sensing properties of the SnO2 films deposited by spray pyrolysis was considered in this paper. It was shown that the addition of Cu in SnO2 even in small concentrations was accompanied by strong changes in the SnO2-based gas sensors performances. The reasons of observed changes were discussed. The conclusion was made that the decrease of response of heavy doped SnO2:Cu-based gas sensors was mainly connected with both structural disordering of heavy doped SnO2:Cu metal oxide, and the appearance of the fine dispersed phase formed in the SnO2 matrix. (C) 2013 Elsevier B.V. All rights reserved.