Water-sodium metabolism and central hemodynamics were studied in 44 males with hypertensive disease whose ages ranged from 17 to 72 and in 10 persons of the control group. It was established that disorders of water-sodium metabolism already occur in the early stages of hypertensive disease. In patients with border-line hypertension a decrease in content of total metabolic sodium and of total body water with elevation of arterial pressure was encountered. The values of total metabolic sodium and total water in the body are restored in stage I of the disease. The increase in the content of total metabolic sodium is most marked in stage III hypertensive disease (without renal and cardiac insufficiency). Accumulation of sodium in the organism of patients wih hypertensive disease closely correlates with a decrease in creatinine clearance. The decrease in the circulating blood volume with the advancement of the disease depends to a great measure on the growing vascular resistance to the blood flow.