The plasma tissue factor (TF) antigen level was measured in patients with disseminated intravascular coagulation (DIC). The plasma TF antigen was detected in normal volunteers, and it was significantly higher in DIC patients than in non-DIC patients. However, in some patients with DIC, the plasma TF antigen level was within the normal range. The plasma TF antigen level in patients with DIC significantly decreased after therapy, but it was not correlated with organ failure or outcome. The plasma TF antigen level in patients with DIC was not correlated with other hemostatic markers. The plasma TF antigen level tended to be higher in DIC patients with nonlymphoid leukemia than in those with lymphoid tumor. TF might be implicated in the occurrence and progression of DIC.