A 28-year-old man with compensated cirrhosis of the liver (Child B) and after 4 episodes of esophageal variceal bleeding received prophylactic endoscopic variceal sclerotherapy in our Gastroenterology Clinic for 8 consecutive months. Sclerotherapy of the esophageal varices had been performed at monthly intervals until variceal obliteration was achieved. Both the intravariceal and paravariceal injection techniques were used and injections were repeated periodically as necessary. On the 8th month, 1 week after the 4th sclerotherapy procedure, the patient complained of swelling on his right shoulder and on his right arm. There was jugular congestion and swelling of his right arm and right shoulder. The patient was hemodynamically stable. An X-ray of brachial venography revealed an obstruction of the vena subclavia dextra. During follow-up, the jugular congestion and swelling of his right arm gradually subsided spontaneously over a 6-month period without any need for medication. There has been no recurrence of his symptoms during the 1-year follow-up period. Now, he is still well clinically. This experience suggests that endoscopic injection sclerotherapy may cause thrombosis of the subclavian vein which have been never seen before.