The purpose of this study was to perform a prospective multicenter evaluation of the patency, complications, and predictive factors of patency for 6-mm expanded polytetrafluoroethylene (ePTFE) grafts used in hemodialysis access. Eighty-six patients were evaluated; the mean age was 55.8 years (range 23-90), 46 patients were female. Patency and complications were assessed at the initial dialysis and 1, 3, 6, 9, and 12 months postoperatively. Kaplan-Meier survival curves were calculated to determine primary and secondary patency, and log-rank analysis was used to determine differences between curves. The Student's t-test was used to compare groups. Primary and secondary patency rates at 1 year were 43% and 64%. Venous line pressures tended to rise over time. Recirculation values and blood flow rates during dialysis showed no correlation to graft patency. These results show that ePTFE provides a suitable secondary choice for vascular access for end-stage renal disease patients in whom an autogenous fistula is not possible. Thrombosis and anastomotic stenosis are common and should be aggressively identified and treated to prolong overall graft survival.