Patients with chronic renal impairment (CRI) are at greatly increased risk for premature vascular disease; however, little is known about its evolution. This paper describes a cohort of patients with CRI and reports study design, baseline demographic and biochemical data, and comparisons with two contemporaneous age- and sex-matched control groups, one with established coronary artery disease and the other without overt vascular disease. Among 369 individuals (median age, 63 years; range, 18 to 88 years; 67% men) with CRI, 34% had a history of vascular disease and 21% had electrocardiographic left ventricular hypertrophy (LVH). Even in those with mild renal impairment (serum creatinine < 2.1 mg/dL), approximately one third had vascular disease and 12% had LVH. A history of hypertension was present in 76% of the CRI group, but as compared with controls, systolic and diastolic blood pressures were not elevated. Low-density lipoprotein (LDL) cholesterol concentration also was not elevated, but CRI was associated with elevated serum triglyceride and plasma homocysteine levels and reduced high-density lipoprotein (HDL) cholesterol, hemoglobin, and serum albumin concentrations. Across the spectrum of CRI, more severe renal dysfunction was associated with lower levels of diastolic blood pressure, LDL and HDL cholesterol, albumin, and hemoglobin, but increased levels of plasma homocysteine. This cross-sectional analysis shows that vascular disease is common in individuals with mild CRI attending a nephrology program and also suggests trends in the levels of a number of potential vascular risk factors with respect to severity of renal dysfunction. These results will be further quantified in a prospective biennial follow-up.