The principle of operation, construction, and properties of gas sensors based on Nasicon and Lisicon are presented. These types of materials are known to exhibit high ionic conductivities and relatively high chemical stabilities at elevated temperatures. Electrocatalytic sensors have been prepared using ceramic technology. Their working principle is based on electric current acquisition, when a voltage ramp is applied to the sensor. The current-voltage plot has a unique shape, depending on the surrounding gas and its concentration. Measurements conducted in mixtures of nitrogen dioxide, sulphur dioxide, and synthetic air are presented.