Predictors of restenosis after stent angioplasty of ostial renal artery stenosis (RAS) and long-term technical success, particularly the influence of gold coating, are unknown. During a 4-year period (1996-2000), we treated 156 consecutive patients with 219 ostial RAS of > or = 70% diameter stenosis. Gold-coated stents were used in 29% of RAS (n = 64); the vessel diameter ranged from 3 to 9 mm. The restenosis rate was 11.4% at 12 months, 12.2% for gold-coated stents and 11.1% for noncoated stents. Restenosis rates were 16% for < or = 4 mm, 17% for 5 mm, 10% for 6 mm, and 0% for > or = 7 mm (P < or = 0.05). In a backward stepwise logistic regression analysis including gold coating, vessel diameter, gender, diabetes, smoking status, as well as lesion diameter stenosis before and after stenting, vessel diameter was found the only independent predictor of restenosis (odds ratio = 0.57; 95% CI = 0.35-0.93; P = 0.02, for an increase in vessel diameter of 1 mm). Gold coating was not a significant predictor (odds ratio = 1.09; 95% CI = 0.39-3.03; P = 0.87). Seven major (4.5%) complications occurred. There were no procedural fatalities. The restenosis rate after stent angioplasty of ostial RAS is influenced by the vessel diameter but not by gold coating.