BACKGROUND Many prosthetic grafts including expanded polytetrafluoroethylene (ePTFE) and polyethylene terephthalate (Dacron) have recently been used for above-knee femoropopliteal bypass. The purpose of this study was to identify the factors affecting patency performance and patient survival. METHODS A multicenter retrospective analysis of 496 patients who received 564 grafts between 1990 and 1999 (325 ePTFE and 239 Dacron). Follow-up extended to 114.5 months, with a mean of 30.8 months (+/-25.9 months). RESULTS The overall primary patency rate for all grafts was 71.4% at 5 years, 73.7% for ePTFE, and 68.9% for Dacron grafts. The secondary patency rates at 5 years were 84.1% for ePTFE, and 83.8% for Dacron. No significant differences were found. The logistic regression analysis revealed that younger age at operation and smoking history were correlated with decreased primary patency rate. The patency rates were unaffected by postoperative administration of oral anticoagulants or antiplatelet agents, although pharmacotherapy contributed to the improvement of survival rates. Renal failure, cerebral infarction and Dacron decreased survival rate. CONCLUSIONS We conclude that the patency performances of prosthetic grafts are satisfying. However, the choice of prosthetic grafts for younger patients or patients with a smoking history need to be carefully considered. Cerebral infarction, chronic renal failure and Dacron grafts may decrease the survival rate. The operative indications should be determined carefully in these cases. The administration of beraprost sodium is recommended for postoperative pharmacotherapy.