Objective: To investigate stable nitric oxide metabolites (NOx), endothelin-1(ET-1), homocysteine (HC), von Willebrand factor (vWF) levels in patients with essential hypertension (EH) and subclinical organ damage (SOD). Design and Method: We included124 patients (45 men and 79 women) with untreated EH (mean age 51.4 ± 6y, mean EH duration 8.5 ± 7y) and 25 healthy volunteers (10 men and 15 women) with comparable age (47.2 ± 7y). Plasma NOx level was measured by spectrophotometry, ET-1, HC, vWF levels were studied with the help of immunoenzyme assay. Results were processed with Statistica 8.0 software. Results: Microalbuminuria (MAU) was detected in 22% of hypertensives, left ventricular hypertrophy (LVH) in 37% of them. NOx, ET-1, HC, vWF levels were significantly higher in hypertensives (43,2 ± 21 μmol/l, 1,2 ± 0,9 fmol/l, 17,9 ± 7,8 μmol/l, 1,3 ± 0,6 mg/dl, accordingly) than in controls (28,3 ± 9 μmol/l, 0,6 ± 0,5 fmol/l, 10,7 ± 5,8 μmol/l, 1,01 ± 0,7 mg/dl, accordingly) (р < 0,05). The concentration of NOx and ET-1were significantly higher in patients with MAU in comparison to others (46,5 ± 22, 31,3 ± 12 μmol/l and 1,3 ± 0,8, 0,5 ± 0,6 fmol/l, accordingly, р < 0,05). NOx, ET-1 levels were correlated with the presence of MAU (r = 0,48, р = 0,007; r = 0,37 р = 0,03, accordingly). HC, vWF levels did not differ between hypertensives with MAU and normoalbuminuria (р > 0,05). In patients with LVH NOx, ET-1, HC, vWF levels were significantly higher (49,9 ± 19 μmol/l, 1,3 ± 1,1 fmol/l, 20,1 ± 7,6 μmol/l, 1,5 ± 0,7 mg/dl, accordingly) than in those without it (39,8 ± 18 μmol/l, 0,8 ± 0,9 fmol/l, 16,5 ± 7,1 μmol/l, 1,2 ± 0,7 mg/dl accordingly), (р < 0,05). NOx concentration correlated with left ventricular mass index (r = 0,44 р = 0,005), interventricular septum thickness (r = 0,36 р = 0,02) and left ventricle posterior wall thickness (r = 0,44 р = 0,006). The vWF level was correlated with the presence of LVH (r = 0,45, р < 0,009). Conclusions: NOx, ET-1, HC, vWF were elevated in hypertensives with LVH, and NOx, ET-1 levels were higher in hypertensives with MAU. The levels of studied endothelial markers were directly correlated with presence of LVH and MAU