The prevalence and risk factors for renal artery stenosis (RAS) and chronic kidney disease (CKD) are unclear in Japanese patients with peripheral arterial disease (PAD). To examine these issues, we performed renal angiography in 410 patients with PAD. Renal function and damage were assessed using the estimated glomerular filtration rate (eGFR) and urinary level of microalbumin (MA). Multiple logistic and multiple regression analyses were used to examine the relationships of potential risk factors with RAS and CKD. In all, 94 subjects (22.9%) had RAS >50% and 45 subjects (11.0%) had RAS >75%. The incidences of an abnormal level of MA and renal insufficiency (eGFR <60 ml min(-1) per 1.73 m(2)) were 37.0 and 60.7%, respectively. RAS > or =50% was associated with critical limb ischemia (CLI; hazard ratio (HR) 2.519; 95% confidence interval (CI) 1.203-5.276, P=0.014), coronary heart disease (CHD; HR 2.143; 95% CI 1.129-4.069; P=0.020) and hypertension (HR 1.907; 95% CI 1.009-3.628; P=0.045). RAS > or =75% had a relationship with hypertension (HR 3.093; 95% CI 1.002-9.548; P=0.048). eGFR was negatively correlated with age, uric acid and CHD (P=0.013), and MA had a significant positive correlation with low-density lipoprotein cholesterol, CLI, age, CHD and diabetes (P<0.001). These results show that the prevalences of RAS and CKD are very high in Japanese patients with PAD; that CLI and CHD are major risk factors for RAS; and that hyperuricemia, hypercholesterolemia and diabetes are risk factors for CKD in PAD. We also found that MA is a simple and noninvasive marker of renal dysfunction and general vascular damage.