Renovascular disease (RVD) in older patients can cause progressive renal insufficiency and even end-stage renal disease (ESRD). The frequency of this clinical problem is not well defined. Renal duplex sonography (RDS) correctly identifies the presence of RVD with an overall accuracy of approximately 95%. Therefore, the purpose of this study was to utilize RDS as a noninvasive tool to identify the presence of critical RVD (> or = 60% diameter-reducing stenosis or occlusion) in patients 50 years of age or older beginning renal replacement therapy. A total of 53 consecutive participating patients were prospectively interrogated. Complete interrogations occurred in 45 of the 53 patients (85%), and 92 of the 103 kidneys (89%). Critical RVD was noted in 10 of 45 patients (22%). RVD was bilateral in 5 patients, unilateral in 5 patients, and there were 4 renal artery occlusions noted. All patients with critical RVD were white (10 of 25 white patients or 40%). Total pack years of smoking as well as associated cardiovascular and cerebrovascular conditions were greater in those patients with critical RVD compared to those without. These results indicate that RDS remains technically feasible as renal blood flow and function decline. Unsuspected RVD possibly contributory to renal insufficiency exists in a significant number of primarily white patients 50 years of age or older beginning renal replacement therapy. These patients are generally smokers with a high frequency of associated extrarenal atherosclerosis The addition of RVD as a separate category of disease causing ESRD would improve U.S. Renal Data System ESRD classification. RVD should be recognized as a cause of ESRD.