The paper analyzes the results of few investigations conducted at the State Research Center for Preventive Medicine, which enrolled patients with permanent arterial hypertension. The magnitude of a white-coat effect, i.e. the elevation of blood pressure (BP), on its measurement by a doctor was estimated in hypertensive patients before long-term antihypertensive therapy. The effect was calculated using the results of 24-hour BP monitoring as the difference between the BP level during a physician's visit and its average daytime values. Then the patients received BP-lowering drugs in the average therapeutic doses for 1-3 months. Long-term antihypertensive therapy with diltiazem, moxonidine, enalapril, lisinopril, telmisartan had no statistically significant impact on a white-coat effect. Long-term treatment with metoprolol and amlodipine resulted in a significant reduction in this effect; the intake of metoprolol virtually nullified its magnitude.