The fabrication of a hydrogen sulfide (H2S) sensor based on polyaniline (PANI)-metal salt (CuCl2) composite is demonstrated. The sensing film was produced by screen printing and spray coating of the sensing material on interdigitated silver electrodes inkjet-printed on a paper substrate. The H2S sensing functionality with respect to pH and metal salt concentration was optimized. In addition, the long term stability and humidity effects on the sensor performance were investigated. The printed chemiresistors showed more than five orders of magnitude change in resistance within 20 min of exposure of 15 ppm H2S at room temperature. The relatively fast kinetics and large response of the sensor can be explained by the formation of Cu2S and subsequent protonation of PANI. In addition, the relatively large roughness and porosity of the paper substrate offers an increased surface sensing area. (C) 2013 Elsevier B. V. All rights reserved.