The effect of total-body cold exposure on plasma concentrations of von Willebrand factor (vWF), endothelin-1 (ET) and thrombomodulin (TM), all of which are considered to be generated from the endothelium, was studied in systemic lupus erythematosus (SLE) patients with and without Raynaud’s phenomenon. The plasma levels of vWF, ET and TM in SLE patients, irrespective of the presence of Raynaud’s phenomenon, were significantly higher than in normal controls even before the cold provocation test. After the cold provocation test, plasma levels of vWF and ET were significantly higher in SLE patients with Raynaud’s phenomenon than in those without and in normal controls. No significant increase in TM was observed in either the SLE patients or the controls. These results suggest that SLE patients, regardless of the presence of Raynaud’s phenomenon, are in a hypercoagulable state and that this state may be further intensified by cold exposure. Hence, it is concluded that we should consider antithrombotic therapy for SLE patients, especially those with Raynaud’s phenomenon, to prevent unwanted activation of the coagulation system and possible endothelial damage.