Inflammasomes are innate immune signaling pathways that sense pathogens and injury to direct the proteolytic maturation of inflammatory cytokines such as IL-1beta and IL-18. Among inflammasomes, the NLRP3/NALP3 inflammasome is the most studied. However, little is known on the molecular mechanisms that mediate its assembly and activation. Recent findings suggest that ROS are produced by NLRP3/NALP3 activators and are essential secondary messengers signaling NLRP3/NALP3 inflammasome activation.