There are many patients suffering from neuropathic pain. Reactive oxygen species (ROS) is thought to be a mediator of neuropathic pain. In addition, neuropatic pain is aggravated by low temperature. However, receptor of ROS and low temperature is unknown. TRPA1 is activated by pain- producing agents such as allyl isothiocyanate or formaldehyde. We hypothesized that TRPA1 is receptor of ROS and low temperature on nociceptor. The purpose of present study is to investigate the validity of this hypothesis using Ca2+ imagining, patch clamp. Deep cooling (<17degC) and ROS activates TRPA1 expressing HEK293 cells. These results indicate that TRPA1 is receptor of ROS and low temperature.