Hyperglycaemia in patients with diabetic mellitus influences directly and indirectly (by the development of advanced glycation end-products and by the stimulation of polyol pathway of glucose metabolism) the development of small vascular damage, including that of the kidney (glomeruli) and heart. The optimal metabolic control of diabetes consisting of the control of glycaemia, blood pressure and lipid metabolism permits effective protection of the kidneys and cardiovascular system. There are several proofs that such management may reduce by more than 50% the development of the increase in urinary albumin excretion, diabetic nephropathy and incidence of cardiovascular events. Patients with diabetic nephropathy should be qualified early for renal replacement therapy, when the values of glomerular filtration rate average 29-15 ml/min/1.73 m².