BACKGROUND The objective of this study was to compare polyester (Dacron) and expanded polytetrafluorethilene (ePTFE) grafts for above-knee femoropopliteal bypass. METHODS Eighty five patients with disabling claudications or limb threatening ischemia suitable for above-knee femoropopliteal reconstruction were randomized into two groups. In the first group the surgery was performed using 8 mm Dacron graft, whereas the patients in the second group were operated using ePTFE grafts. RESULTS The primary patency rates for Dacron and ePTFE were 100 %, and 88.37 % (p < 0.05), while secondary patency rates were 83.3 % and 75 % (p > 0.05) respectively. The early limb salvage rates for Dacron and ePTFE were 100 % and 97.7 % (p > 0.05). Early (30-day) complications (bleeding 2.38 % and 2.32 %; wound infection 11.9 % and 11.63 %) occurred in both groups with similar frequency (p > 0.05). The patients were followed up over a period of 6 to 12 months (mean 8.3 +/- 3.6 months). The overall mortality rate in the follow-up period was 2.38 % (one patient) for Dacron and 6.98 % (three patients) for ePTFE group (p > 0.05). Late graft infection was noted in three patients (7.1 %) in Dacron, and two patients (4.65 %) in ePTFE group (p > 0.05). Primary patency rates were not significantly influenced by obesity, diabetes, hypertension, hyperlipidemia, cigarette smoking, (p > 0.05). However, poor run-off (only one crural artery patent on preoperative angiography) significantly decreased patency of both grafts and favored the use of ePTFE graft (p < 0.05). CONCLUSIONS This study confirms that both materials are suitable for above-knee femoropopliteal reconstructions. Above-knee femoropopliteal bypass does not have a good long-term prognosis in the presence of poor run-off.