ZnO-coated single-wall carbon nanotube (ZnO–SWNT) network sensors were fabricated by forming a SWNT network on the Pt electrode patterned SiO 2 /Si substrate using a spin coating and depositing the ZnO nanoparticles on the SWNT network using rf magnetron sputtering, and their dimethyl methylphosphonate (DMMP) sensing properties were investigated. ZnO nanoparticles of 7–8nm size were successfully deposited on SWNTs and their surface coverage was controlled by the deposition time. The ZnO–SWNT network sensors stably and reversibly responded to DMMP even at room temperature. In addition to low temperature detection, the response behavior of network sensors was changed from p-type to n-type with deposition time.