Urokinase (UK) [EC 3.4.99.26] is a serine protease that activates plasminogen to plasmin, which in turn degrades fibrin clots. Hence, UK finds its value as an important anti-thromboembolic drug. Plasmin has diverse physiological roles apart from its fibrinolytic role in the regulation of blood clotting. It has been implicated in complement activation, cell migration, wound healing, and generation of localized extracellular proteolysis during tissue remodelling, pro-hormone conversion, carcinogenesis and neoplasia. Among the plasminogen activators, UK provides a superior alternative for the simple reasons of its being more potent as compared to tissue-plasminogen activator and non-antigenic by virtue of its human origin unlike streptokinase. Based on these observations, UK is a very popular cardiovascular agent. Hence, UK, as one of the most potent plasminogen activators is attracting a great deal of attention. We will summarize recent patents related to the occurrence, mechanism of action, structure and function, physico-chemical properties, in vitro production, cloning and expression, purification and applications of UK.