Hypertension, the most significant cardiovascular risk factor, appears twice more often in persons with diabetes compared to nondiabetic population. A high percentage of complications (40 - 70 %) in diabetic population is caused just by hypertension. That is why timely diagnosis and consistent treatment of hypertension is stressed in patients with diabetes. Blood pressure of young people with type I diabetes is proved to be higher compared to their healthy peers. Both in people with type I and type II diabetes are, compared to other populations, more frequent incidence of a phenomenon called “white coat”, increased variability in blood pressure, and higher percentage of non-dippers with high blood pressure. They are on a higher risk for diabetic nephropathy and its quicker progression. Therefore it is desirable to start medication and alter its combination after confirming blood pressure values by ambulatory monitoring so that the blood pressure is well controlled not only by day but also during sleep and early in the morning.

        Key words: Diabetes mellitus - Hypertensive disease - Ambulatory monitoring of blood pressure - Daily blood pressure - Sleep blood pressure - Non-dippers