Sensing properties to dilute volatile sulfides such as H2S, CH3SH, and (CH3)(2)S have been investigated for CdGa2O4 thick film sensor prepared by sol-gel method. Cadmium nitrate and gallium nitrate were mixed in an aqueous solution of citric acid. After reflux and evaporation of the solution, the gel obtained was ground and calcined at 800degreesC for 8 h in air. The CdGa2O4 sensor prepared using the powder calcined at 800degreesC showed high sensitivity as well as good selectivity to dilute CH3SH at 300degreesC. In particular, the CdGa2O4 sensor showed sensitivity as high as 20 even to 0.01 ppm CH3SH. The crystal structure and surface morphology were examined by means of X-ray diffraction analysis and scanning electron microscopy, respectively.