During a 32-month period, 25 modified self-expandable endovascular stents were placed in 20 hemodialysis access sites to treat 21 stenoses and four occlusions in 19 patients. All stenoses were initially dilated with a high-pressure balloon. The initial success rate was 90% (18 of 20 access sites). The stents were patent from 0 to 960 days (mean duration of follow-up, 309 days). At 2 years follow-up, the patency rates were as follows: primary, 25%; secondary, 34%; and tertiary, 42%. The morbidity rate associated with this procedure was 15% (three of 20 sites); the mortality rate, 5% (one of 19 patients). All five complications (graft or native-vein thrombosis [n = 2], nerve deficits [n = 2], and death secondary to sepsis [n = 1]) occurred in three patients early in the study, before the use of prophylactic antibiotics and refinements in technique. The best results occurred in patients in whom the stenosis or occlusion affected a large vein that had no acute angle and was away from venous confluences such as the femoral and iliac regions.