The aim – to study the frequency of detection, the clinical course of resistant arterial hypertension (RAH). Material and methods. Among surveyed 436 individuals suffering from essential hypertension, 47 patients (10.8 %) with RAH were found. The control group included 90 patients with controlled arterial hypertension. All patients underwent general clinical examination, office blood pressure measurement, determination of microalbuminuria, total cholesterol, triglycerides, uric acid, serum creatinine, calculated GFR, fasting glycemia, test of glucose tolerance, echocardiography, ultrasound of the internal carotid artery. Results. In 28 (60 %) of 47 treatment-resistant patients qualitative test for microalbuminuria was positive, whereas in the control group – in 26 (29 %) patients. Albumin/creatinine ratio in treatment-resistant patients was significantly higher than in individuals with controlled arterial hypertension (186.00±5.16 and 124.00±4.96 mg/g respectively; P<0.05). Serum creatinine concentration was significantly higher (99.60±1.52 and 80.10±1.21 mmol/l, respectively; P<0.05), and GFR assessed by Cockcroft – Gault formula was significantly lower (83.50±3.26 and 102.00±4.06 ml/min/1.73 m2 respectively; P<0.05) in patients with RH compared to patients with controlled arterial hypertension. In 21 (45 %) patients with RAH, apart from microalbuminuria, we observed GFR reduction. The concentration of total cholesterol and triglycerides in RAH patients exceeded the normal range and was significantly higher compared to group with controlled arterial hypertension and in 69.1 % of them lipoprotein metabolism disorders were found. In RAH group average fasting glucose levels were slightly higher than normal and were significantly higher compared to patients with controlled arterial hypertension (P<0.05) and after glucose load they were also significantly higher than in patients with controlled arterial hypertension (P<0.05), while the percentage of patients with diabetes mellitus in both groups was not significantly different. Among patients with RAH in 19 (39 %) hyperuricemia was detected and uric acid levels were significantly higher (P<0.05) than in patients with controlled arterial hypertension. Signs of left ventricular hypertrophy were found in all patients with RAH, this group had significantly higher average left ventricular mass index compared to controlled arterial hypertension group (234.20±4.26 and 208.18±6.30 g/m2, respectively, P<0.05). Moreover, intima – media thickness was higher compared to the controlled arterial hypertension group (1.18±0.04 and 9.8±0.03 mm respectively, P<0.05). Conclusions. RAH course was associated with coronary artery disease (51 %), metabolic syndrome (49 %), more distinct target organ damage (left ventricular hypertrophy, thickening of intima – media, hypertensive nephropathy worsening). These changes may be reversed by effective blood pressure control.