How animals sense environmental cues, integrate information in the nervous system, and produce appropriate behaviors is a fundamental question in neurosciences. We study nociception, the sensation of noxious stimuli, and resulting aversive behaviors in C. elegans. Thanks to the unique set of experimental tools offered by this model, we comprehensively address the question at the molecular, neural, and behavioral levels. Nociception mechanisms are involved in the sensation of pain in human. Since the worm shares many genes with human and the molecular pathways of nociception are largely conserved, the present research might provide insights for new therapeutic strategies in pain management.