Background: Angiotensin-receptor blockers (ARBs) blunt progression of advanced diabetic nephropathy, but their long-term renal effects in other patients are not clear. Objective: To examine the long-term renal effects of telmisartan versus placebo in adults at high vascular risk. Design: Randomized trial. Patients were randomly assigned by a central automated system between November 2001 and May 2004 and were followed until March 2008. Participants and investigators were blinded to intervention status. Setting: Multicenter, multinational study. Patients: 5927 adults with known cardiovascular disease or diabetes with end-organ damage but without macroalbuminuria or heart failure who cannot tolerate angiotensin-converting enzyme inhibitors. Intervention: Telmisartan, 80 mg/d (n = 2954), or matching placebo (n = 2972) plus standard treatment for a mean of 56 months. Measurements: Composite renal outcome of dialysis or doubling of serum creatinine, changes in estimated glomerular filtration rate (GFR), and changes in albuminuria. Results: No important difference was found in the composite renal outcome with telmisartan (58 patients [1.96%]) versus placebo (46 patients [1.55%]) (hazard ratio, 1.29 [95% CI, 0.87 to 1.89]; P = 0.20). Among the telmisartan and placebo groups, 7 and 10 patients had dialysis and 56 and 36 patients had doubling of serum creatinine, respectively (hazard ratio, 1.59 [CI, 1.04 to 2.41]; P = 0.031). Albuminuria increased less with telmisartan than with placebo (32% [CI, 23% to 41%] vs. 63% [CI, 52% to 76%]; P = 0.001). Decreases in estimated GFR were greater with telmisartan than with placebo (mean change in estimated GFR, -3.2 mL/min per 1.73 m2 [SD, 18.3] vs. -0.26 mL/min per 1.73 m2 [SD, 18.0]; P < 0.001). Limitation: Only 17 participants had dialysis. Conclusion: In adults with vascular disease but without macroalbuminuria, the effects of telmisartan on major renal outcomes were similar to those of placebo. Primary Funding Source: Boehringer Ingelheim. © 2009 American College of Physicians.