Thick films of LaNiO₃ having perovskite structure impregnated with indium and bismuth oxides have been used as sensing material for acetonitrile (CH₃CN) gas. The sensor response for CHICN is quite good with an excellent recovery for partial pressure from 3 ppm to 20 ppm between 200 and 250℃. LaNiO₃ alone has exhibited low response, but after impregnation of In₂O₃ and Bi₂O₃ have given increased sensitivity even with 3 ppm partial pressure of CH₃CN at 200℃. It is assumed that CH₃CN is undergoing oxidation reaction on surface of the film.