The term microalbuminuria stands for an increased urinary excretion of albumin undetectable by routine methods for determination of proteinuria. Microalbuminuria is found in a substantial proportion of patients with diabetes, arterial hypertension and in the elderly. New data has provided strong evidence that albuminuria not only indicates early glomerular damage but also widespread endothelial dysfunction, early atherogenesis and increased cardiovascular and cerebrovascular risk. It has been shown that angiotensin converting enzyme inhibitors have a potential to decrease urinary albumin excretion, which confirms their well-established nephro- and vasoprotective action.