Gas sensors based on solid electrolytes have been explored extensively in recent years, especially from growing concerns to environmental issues. Among the Various solid electrolyte sensors, the group of devices based on the mixed-potential gas-sensing principle has been paid special attention due to its attractive performances as well as unique working mechanism. These devices, if designed properly, can exhibit high sensitivity and selectivity to redox gases in oxygen containing atmospheres even at high temperature, showing promise of being applied for combustion exhaust monitoring. This article aims at over-viewing recent progress in the mixed-potential type gas sensors. Particular attention is focused on our original work about the zirconia-based sensors using oxide electrodes for detecting various gases such as H-2, CO and NOx at high temperatures.