We experienced a case of subclavian steal syndrome (SSS) with a specific form of obstruction of the right proximal subclavian artery. The patient was a 44-year-old man who complained of numbness of the right hand. Right carotid-subclavian artery anastomosis was performed under general anesthesia. The obstructed segment was a fibrous cord, 3.5 cm in length and 2.0 mm in diameter. Postoperatively, the patient was free from the symptom. In the Japanese literature, 73 cases of SSS were reported from 1965 to 1986, and the etiology was mentioned in 64 cases. In 28 cases the cause was aortitis syndrome (43.8%), in 22 cases arteriosclerosis (34.4%), in 13 cases congenital malformation (20.3%), and in 1 case iatrogenic lesion (1.6%). These data indicated that SSS caused by congenital malformation was not so rare as previously believed. Of 13 cases with congenital malformation, our case and 3 other cases had similar aspect in clinical features. All 4 patients were middle-aged men (aged 34, 26, 45 and 44 years) with a fibrous cord at the proximal portion of the right subclavian artery. None had any other cardiovascular anomalies.