PURPOSE OF REVIEW: To describe the relationship of renal disease and metabolic syndrome with cardiovascular disease and explore the role of toxic solutes retained due to renal impairment as mediators of cardiovascular risk. RECENT FINDINGS: Metabolic syndrome and chronic kidney disease are related. Chronic kidney disease is partly caused by, but also mediates, some of the adverse effects of metabolic syndrome. Uremic toxins with potent effects have been identified. Examples include the nitric oxide synthase inhibitor asymmetric dimethyl arginine - this substance accumulates as renal function declines and has a strong relationship with cardiovascular events and mortality in a variety of populations. The effect of asymmetric dimethyl arginine in causing arterial stiffness, a phenomenon which has been linked with risk of vascular disease, offers a mechanistic explanation for the importance of this substance. SUMMARY: A pathophysiology that links renal impairment with cardiovascular risk has long been suspected and is being elucidated through the effects of uremic toxins.