Tumor necrosis factor-± (TNF±) is a central mediator in the pathogenesis of sepsis. It also interferes with the hemostatic system and exerts a net procoagulant effect. Since TNFa may contribute to thrombotic complications in sepsis patients, we determined markers of thrombin activation, parameters of the fibrinolytic system (D-dimer, tissue plasminogen activator antigen (tPA), urinary type plasminogen activator antigen (uPA), plasminogen activator inhibitor antigen (PAI-1)) and von Willebrand factor antigen (vWF) in 30 patients with sepsis or septic shock. All patients were treated with standard therapy, but 14 patients were treated additionally with an anti-TNF± monoclonal antibody (MAK 195F); 16 patients served as historical controls. No significant effect of the antibody on the parameters of the hemostatic system could be determined. Our data speak against a modulation of coagulation or the fibrinolytic system by the monoclonal anti-TNF± antibody MAK 195F in this cohort of sepsis patients.