Proteases are everywhere from prokaryotes to eukaryotes, from virus to bacteria and in all human tissues, playing a role in many biological functions. Among these functions, the inflammatory reaction is of particular interest. In inflamed tissues, proteases can have a microbial and/or host origin and are involved t only in tissue remodeling, but also in specific signaling to resident or inflammatory cells, thereby contributing to the innate immune response. This volume presents all advances in our kwledge of the role proteases and their inhibitors play in various diseases associated with inflammatory response. Mechanisms involved in protease signaling to cells are presented, and the different types of proteases that are present at inflammatory sites and their effects on the course of inflammation are discussed. Finally, the evidence for considering proteases and their receptors as potential molecular targets for therapeutic interventions in the treatment of inflammatory diseases is discussed in the context of specific organ inflammatory pathologies (the lung, gastrointestinal tract, skin, joints, etc.).