Elevated levels of circulating procoagulants like tissue factor may increase the risk of systemic coagulation activation, thrombin generation, and consumptive coagulopathy. I measured procoagulant activity in plasma by using a clot-based assay that incorporated normal plasma to replace missing factors, corn trypsin inhibitor to block contact activation, factor VIIa to improve sensitivity to tissue factor activity, and anti-tissue factor antibodies to measure tissue factor-specific activity. Procoagulant activity was evaluated in 58 trauma patients. Trauma patients without coagulopathy (n = 50) showed 5-fold higher procoagulant activity than did control subjects (P < .001), whereas trauma patients with coagulopathy (n = 8) showed 10-fold higher activity than control subjects (P < .001) and 2-fold higher activity than trauma patients without coagulopathy (P = .03). In control subjects, tissue factor activity was below the detection limit of the assay. Tissue factor activity was 3- to 4-fold higher in trauma patients with coagulopathy vs patients without coagulopathy (P = .002). Trauma patients with coagulopathy have increased circulating tissue factor activity.