We report here the high butane sensitivity and selectivity exhibited by nanoparticles of SnO2 prepared by a citrate-nitrate gel combustion process. Using the synthesized powders, the sensitivity towards 500, 1000 and 5000 ppm n-butane has been measured at various operating temperatures from 350 degrees C to 500 degrees C. The powder calcined at 600 degrees C exhibited a sensitivity of 91 +/- 0.5% towards 1000 ppm n-butane with a recovery time of 15 s at an operating temperature of 350 degrees C. We have explored the effect of size on both butane gas sensitivity and selectivity and found that the reduction of particle size of the order of 10 nm could result in a remarkable increase in the response of the sensor towards butane compared to other reducing gases like H-2 and CH4. The most important observation that emerged from our studies is a combination of sensitivity and selectivity that has been achieved using SnO2 nanoparticles without the addition of any noble metal catalyst such as Pd or Au. (C) 2015 Elsevier Ltd. All rights reserved.