ObjectiveAn increased frequency of the angiotensin converting enzyme (ACE) D variant has recently been reported in patients with atheromatous renal artery disease (RAD), whereas controversy exists on the risk of coronary artery disease (CAD) associated with this polymorphism. In spite of the frequent coexistence of RAD and CAD, no studies have specifically compared ACE insertion/deletion (I/D) polymorphism in patients with coronary versus renal artery disease or defined the risk of each disease associated with the D variant.DesignWe designed a large case–control study of subjects for whom objective renal or coronary angiographic documentation was available.Methods and resultsWe analysed ACE I/D genotype and clinical–biochemical data of a total of 942 subjects (123 patients with and 137 without angiographic evidence of RAD, 420 patients with and 262 without angiographic evidence of CAD). Renal (with and without RAD) and coronary patients were similar for most conventional risk factors. There was no difference inDDfrequency between CAD and CAD-free patients (38.1 versus 33.6%, NS) andDDhomozygosity was not associated with CAD risk (OR = 1.27, 95% CI = 0.82–1.98). In contrast, theDDgenotype was more frequent in RAD than in RAD-free patients (54.5 versus 39.4,P<0.05) and was associated with a 2.25-fold increased risk of RAD in both the univariate and multivariate logistic regression models. Additional predictors of RAD were age and creatinine. In RAD/RAD-free patients with angiographically documented CAD,DDhomozygosity was confirmed to be preferentially associated with RAD (P<0.05).ConclusionsACE D variant is preferentially associated with atherosclerotic renal rather than with coronary disease, despite similar exposure to atherogenic noxae.DDhomozygosity confers a 2.25-fold increased risk of RAD.