A LaGaO 3 -based electrochemical sensor in the amperometric mode was demonstrated as highly sensitive to NO in the temperature range 500-700°C. Sensor performance was found dependent on the Ni doping of LaGaO 3 . Using optimized electrode materials, highest sensitivity was achieved as high as 2409 A/decade (at 550°C) when Ni doping to electrolyte was 7 mol%. The selectivity of the sensor was found very high to NO with respect to the typical coexisting gases in the exhaust environment. The sensing principle was observed to follow the mixed potential behavior.