A thick film catalytic gas sensor operable at a temperature of 82 °C in the presence of UV-LED (ultra violet-light emitting diode) has been developed to measure hydrogen concentration in the range of 0.5–5%. The sensing material as a combustion catalyst consists of TiO 2 (5 wt%) and Pd/Pt (20 wt%) supported on γ-Al 2O 3 powder. The reference material to compensate the heat capacity of it in a bridge circuit is γ-Al 2O 3 powder. A platinum heater and the sensor materials were formed on an alumina plate by a screen printing method, followed by heat treatment. The effect of UV irradiation in the presence of photocatalyst TiO 2 on the sensor response, response and recovery time has been investigated. The reduction of operating temperature from 253 to 82 °C for hydrogen gas sensing in the presence of UV radiation is attributed to the enhanced activity of the chemisorbed oxygen ions which facilitate a higher rate of reaction between O 2 and H 2.