Methane detection in ambient condition has become essential as it is being increasingly used as compressed natural gas in many industrial processes and for domestic and transportation purposes. Hence, in this work, we report a room-temperature methane sensor based on polyaniline/zinc oxide (PANI/ZnO) nanocomposite. The PANI/ZnO nanocomposite was prepared by chemical polymerization of aniline in the presence of ZnO nanoparticles. Electron microscopy results revealed the successful formation of nanocomposites with rod-like ZnO nanoparticles embedded into the network of nanofibrillar PANI matrix. The PANI/ZnO nanocomposites exhibited a high response to methane at room temperature within a short response time of 20 s for a methane concentration (500 ppm) much lower than its flammability limit. Moreover, the humidity dependence of the sensor response was found to be very low. POLYM. ENG. SCI., 58:1438-1445, 2018. (c) 2017 Society of Plastics Engineers