Three members of the S100 family of calcium-binding proteins comprise a new group of proinflammatory molecules released by phagocytes. A novel inflammatory syndrome defined by extraordinarily high expression of S100A8 and S100A9 confirmed recent observations in vitro demonstrating a role of these proteins during recruitment of leukocytes. S100A12 directly activates endothelial cells, mononuclear phagocytes and lymphocytes through interaction with the receptor for advanced glycation end products. Thus, these S100-proteins are attractive targets to modulate inflammation.