A survey is given of recent data pertaining to the presence of components of the fibrinolytic system in the vascular wall. Activators and inhibitors of fibrinolysis were shown to be present in the vessel wall, while activators were mainly found in the endothelial cells, and inhibitors in the media. Activators will be released into the circulation by a variety of stimuli. Among these stimuli are compounds formed or released during coagulation and thrombus formation, thus indicating how coagulation or thrombosis might induce increased fibrinolysis. Abnormal fibrinolytic activity in the vessel wall in relation to thrombosis is discussed.