Reduced plasma fibrinolytic activity may be a risk factor in venous and arterial thrombotic disease. Resting plasma fibrinolytic activity and fibrinolytic potential after ten minutes of venous occlusion were compared in 100 patients with peripheral vascular disease of varying severity and 20 age-sex matched controls. The fibrinolytic assay used was the euglobulin lysis time. Resting plasma fibrinolytic activity was significantly reduced in patients with a recent arterial thrombosis (p = 0.02) and ischaemic rest pain (p = 0.008) compared with controls. Fibrinolytic potential after venous occlusion was significantly reduced also in patients with a recent arterial thrombosis (p = 0.02) and ischaemic rest pain (p = 0.05) compared with controls. There were no significant differences between patients with claudication and controls. A reduced plasma fibrinolytic activity has been confirmed in patients with peripheral vascular disease and fibrinolytic potential may be a superior method of assessment as the euglobulin lysis time after venous occlusion is independent of the fibrinogen concentration. It remains uncertain whether the finding of reduced plasma fibrinolytic activity in patients with peripheral vascular disease is cause or effect and whether the finding has prognostic significance.