This paper reports a selective method of sensing hydrogen sulphide in gaseous state using silver nanoparticle decorated single-walled carbon nanotubes (SWCNT) at room temperature. The transduction platform is a simple resistor which was constructed by drop-casting of a random network of silver nanoparticle decorated carbon nanotubes onto a channel joining two electrodes. This study shows the differential sensing of hydrogen sulphide with respect to interfering analytes such as carbon monoxide and nitric oxide, displaying the different mechanisms involved in the sensing of the gases. These results indicate the possibility of fabricating simple devices with low power consumption based on flexible plastic substrate for selective sensing of gaseous molecules at room temperature by appropriately functionalizing the carbon nanotubes (CNTs).