Inflammation is a key player in the development of an increasing amount of diseases. The soluble urokinase plasminogen activator receptor (suPAR) is a highly flexible molecule with intrinsic chemotactic properties. This glycoprotein has been evaluated as a biomarker of inflammation, immune activation, organ damage and clinical outcome in several pathologies, including cardiovascular disease, hepatitis, renal disorders and rheumatic pathologies. The use of this early warning inflammatory biomarker could potentially improve the prediction of the severity of these diseases and mortality. In the present paper, we describe the general characteristics of suPAR and its intriguing role as a biomarker in different inflammatory diseases.