Superficial thrombophlebitis is a common finding in Behçet's disease. However, the potential life-threatening complication of superior vena cava (SVC) syndrome due to thrombotic occlusion is a rare manifestation and usually occurs several years after the onset of the diagnosis. The authors describe a twenty-nine-year-old Arab man who had an acute thrombosis of the SVC as the presenting manifestation of his Behçet's disease. The patient was successfully treated with thrombolytic and anticoagulant therapy, and during follow-up no relapse was observed. Behçet's disease should be suspected in young patients presenting with thrombosis of the SVC and without evidence of a hypercoagulable state.