Sixty-two first episodes of aortofemoral (eight patients) or aortobifemoral (42 patients) bypass thrombosis were operated upon in 50 patients between 1980 and 1985. There were 47 men and three women whose mean age was 58 years. Retrograde thrombectomy through the distal anastomosis was achieved in all cases by using either a balloon catheter or Vollmar rings. If thrombectomy was impossible, revascularization was ensured by an extraanatomic bypass or complete replacement of the graft. Angioplasty, repeat distal anastomosis or femoropopliteal bypass of the native runoff artery were done in 55 (89%) operations. The cause of thrombosis was elucidated in 45 cases. Suture line stenosis and atheromatous stenosis of the native runoff artery were the two most common causes. Three patients died and two required above-knee amputation in the immediate postoperative period. Contralateral embolism occurred in two patients undergoing retrograde thrombectomy. Mean follow-up was 47 months. Thrombectomy was possible in 51 or 62 prosthetic thromboses (Group I). Thirty-nine of these grafts have remained patent. Twelve instances of repeat thrombosis occurred, requiring either repeat thrombectomy or a new bypass. Primary patency in group I was 97.8%, 81.2%, and 71.3% at one, three, and five years, respectively. Thrombectomy was impossible in 11 graft thromboses (Group II). A new bypass was performed in all 11 cases. Primary patency in Group II was 100%, 75% and 50% at one, three, and five years, respectively. Retrograde thrombectomy combined with treatment of native runoff artery anomalies can restore long-term patency when thrombosis occurs late after aortofemoral bypass and is associated with low mortality and morbidity.