Changes in renal function produced by hypertension appear to be associated with higher cardiovascular morbidity and mortality. Indices of altered renal function (eg, microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance, or overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The International Nifedipine GITS study: Intervention as a goal in Hypertension Treatment (INSIGHT) study assessed the role of proteinuria as a very powerful risk factor. Several studies demonstrated that microalbuminuria is a predictor of cardiovascular disease. It has been shown that the presence of microalbuminuria in primary hypertension carries an elevated cardiovascular risk. Furthermore, recent data indicate that even minor derangements of renal function are associated with an increase in cardiovascular risk factors, and promote progression of atherosclerosis. All these parameters should routinely be evaluated in clinical practice, and in the future must be considered in any stratification of cardiovascular risk in hypertensive patients.