A process is provided for measuring a gas concentration with at least one thermal measuring element. The thermal measuring element is operated by pulses. A measured value of the gas concentration in the environment of the measuring element is obtained from the evaluation of the response of the measuring element to at least one single pulse by determining transient states of the thermal measuring element. From this the measured value of the gas concentration in the environment of the measuring element can be derived, during the imposed pulse based on electric measured variables.