The sensing performance of the mixed-potential-type total NOx sensor based on laminated yttria-stabilized zirconia (YSZ) sheets was improved by the attachment of oxidation-catalyst electrode. It was found that pure Pt was the best material for the catalyst electrode among the four Pt-based metals examined. The addition of 20 vol.% resin to Pt-electrode paste was quite effective to improve the catalytic activity of the electrode. The obtained sensor could measure total NOx concentration down to 10 ppm at 600 degreesC. The use of the oxidation-catalyst electrode was found to decrease largely the interference of reducing gases (C3H8 and CO) to the NOx sensitivity. (C) 2004 Elsevier B.V. All rights reserved.