Tin dioxide (SnO2) and vanadium pentoxide gas sensors were fabricated to detect carbon monoxide (CO) gas at 75 ºC. SnO2 exhibited a high response to CO gas, SnO2 gas sensor selected CO gas in the presence of five gases such as methane, Hydrogen sulfide, ethanol, methanol and Nitrogen dioxide. SnO2 sensor showed the lowest Limit of Detection (LoD) compared to its counter, the lower LoD could be used to detect CO gas at the lowest parts per billion concentrations.