Renal artery stenosis (RAS) is a relatively uncommon but important potentially reversible cause of renal failure. Little is known about the natural history of ischemic renal disease secondary to RAS. In previous reports, these researchers examined the incidence and risk factors associated with RAS. The study presented here investigates the long-term follow-up of these patients, specifically the effect of RAS on 4-yr, all-cause mortality in a group of 1235 patients undergoing diagnostic cardiac catheterization and abdominal aortography. A total of 1235 consecutive patients undergoing cardiac catheterization also underwent an abdominal flush aortogram. Significant RAS was considered present if one or more renal artery had 50% or greater narrowing in luminal diameter. Four-year unadjusted survival for patients with RAS was 65% compared with 86% for patients undergoing catheterization without significant RAS. Factors associated with decreased 4-yr survival included increased age, increased serum creatinine, presence of RAS, peripheral vascular disease, congestive heart failure, diabetes, hypertension, and reduced ejection fraction. Using the Cox proportional hazards model, the factors associated with decreased 4-yr survival were the presence of significant RAS, reduced ejection fraction, elevated serum creatinine, and symptoms of congestive heart failure. These observations indicate that the presence of significant RAS is a strong independent predictor of 4-yr survival in this patient population.