Protease activated receptor (PAR)s, a four-member family of seven transmembrane G-protein-coupled receptors (GPCRs), can be cleaved by certain serine proteases within the extracellular amino terminus and exposes a tethered ligand domain, which binds to and activates the receptors to initiate multiple signaling cascades.Therefore, these PAR-activating proteases are named as agonists of PARs.Since many of these proteases are produced during inflammation, PARs make important contributions to inflammatory tissue responses including exudation of plasma components, inflammatory cell infiltration, tissue damage and repair etc.in inflammation.In recent years, there has been considerable interest in the role of PARs in allergic inflammation, the fundamental pathologic changes in allergy.Since serine proteases have long been discovered to be actively involved in the pathologic process of inflammation, and large amount of information on PARs are accumulated over the last two decades, we summarize the role of PARs in allergy, which will help us to better understand the roles of serine proteases as agonists or antagonists of PARs in allergy.