Background Placement of renal-artery stents has a high technical success rate in atherosclerotic renovascular disease, but little is known about the clinical benefits of the procedure. We monitored renal function serially before and after stent insertion in patients with renovascular renal failure. Methods Renal function was assessed before and after stent placement by means of serial serum creatinine values in 32 patients with atherosclerotic renal-artery stenosis. The effect on the progression of renal failure was analysed in 23 patients by comparison of the reciprocal slopes of serum creatinine versus time plots before and after stent placement. Findings 33 transluminal stents were placed in 32 patients with atherosclerotic renovascular disease. Immediate patency was achieved in all cases; the angiographic restenosis rate at 6 months was 12% (n=24). One patient died after a procedure-related haemorrhage. Median diastolic blood pressure was significantly lower after stenting than before (95 [IQR 86–103] vs 87 [81–90] mm Hg; p>0·01) but the requirement for antihypertensive drugs was unchanged. Renal function improved or stabilised in 22 (69%) of the 32 patients. Progression of renal failure was significantly slowed after the procedure; the mean (SE) of the slopes of reciprocal serum creatinine values was −4·34 (0·85) L μmol−1 day−1 before stent placement, and −0·55 (1·0) L μmol−1 day−1 after stent placement (p< 0·01, two-sample t test). Interpretation Renal-stent placement in selected patients slows the progression of renovascular renal failure and may delay the need for renal replacement therapy.