Introduction. One of the major concerns of modern medicine is the use of new, long-acting antihypertensive drugs. Numerous studies have confirmed the importance of correct treatment of hypertension to reduce cardiovascular morbidity and mortality. Physicians now have a choice of a wide range of antihypertensive drugs with numerous evidence of their efficacy, but which often cause side effects limiting their widespread use. Benzituron or S-benzylisothiourea chloride is referred to a new range of hypotensive substances, isothiourea derivatives, able to reduce and to stabilize the level of the arterial blood pressure.  The solution of the benzituron, in dosage of 2 mg/kg shows a noticeable hypotensive and antihypertensive action, with duration from 4 to 5 hours.   Aim of the study.  To evaluate the effect of benzituron on blood pressure and heart rate on the background of adrenergic receptor blockade with propranolol.  Materials and methods. The experiments were performed on 14 cats 2-4 kg body weight anesthetized with 30% urethane solution (500 mg/kg) and chloralose (50 mg/kg) administered intraperitoneally, followed by blood pressure and heart rate monitoring at different intervals of time.  Results. The 0.2 mg/kg propranolol solution was administered intravenously with effect assessment at 2 and 5 minutes, followed by 5 minutes intravenous administration of isoprenaline solution 0.005 mg/kg, then 2 mg/kg benzituron dissolved in 1,5 ml physiological saline solution with effect recording at certain time intervals. Isoprenaline was injected to demonstrate β-adrenoceptor blockade by propranolol. Subsequent intravenous injection of benzituron resulted in a decrease in blood pressure at the 60th minute.  Conclusions. Benzituron in the dose of 2 mg/kg exerts hypotensive effect on the background of blockade of β-adrenoreceptors.