Electronic gas flow meters are expected to replace the current mechanical devices. One of the promising solutions is based on thermal MEMS sensor. In this paper, a novel system is introduced that combines a MEMS gas flow sensor and its interface circuit. A 15 bits ASIC is implemented to interface the sensor to an external processor through a standard serial communication. The CMOS 0.13 micrometer ASIC consumes total power of 2.67mW when operating in the continuous read mode. On-demand read mode is supported to lower the power consumption. The total system SNR is 86dB.