In this research, Multi-walled carbon nanotube based gas sensors are used to detect gas molecules of H2S mixed with natural gas. The gas sensors, in which the nanotubes laid on the interdigitated electrodes (IDE), were fabricated using conventional photolithography and sputtering process. The electrical resistance response to H2S gas mixture was investigated at different temperatures. The results show that the response of MWCNT based gas sensors to 160 ppm H2S were excellent at working temperature as low as 70oC. This suggests that MWCNTs could be a good candidate material for H2S detection at low temperatures even in room temperature.