Operating temperature is crucial for a Polysilicon Multi-User Micro electro-mechanical system Processes (PolyMUMPs) gas sensor considering the serious impacts on sensors' selectivity and reliability. While it is difficult to measure this operating temperature because the size of the sensor. This paper studies the characterization of micro-heater and temperature sensor made of gold metal, embedded in the device. The measured resistance for the temperature sensor is found to be close to the modelled values within 0.69 error. Temperature coefficient of resistance (TCR) of the temperature sensor in a range of 25-105°C is found. TCR increases Iinearly with increasing the temperature and decreases Iinearly with decreasing the temperature. It was found to be 0.00326/°C for the increasing temperature and 0.0034/°C for the decreasing temperature, compared to 0.00325/°C reported TCR for gold in the literature, with an error of 4.12 and 4.37, respectively. © 2018 IEEE.