To assess the correlation between endothelial dysfunction and the serum levels of biomarkers of inflammation, remodelling and oxidative stress in essential hypertension, 78 treatment-naïve essential hypertensives (mean age 43 years) underwent measurement of endothelial dysfunction, using the maximal acetylcholine-induced forearm vasodilation and serum levels of adhesion molecules, selectins, chemokines, metalloproteinases, copper, zinc, selenium, vitamins, homocysteine, malondialdehyde, erythrocyte glutathione peroxidase and erythrocyte superoxide dismutase. Mean (+/-s.e.m.) maximal acetylcholine-induced vasodilation was 367+/-20%. Patients with a more impaired acetylcholine-dependent vasodilation (first tertile) had increased levels of e-selectin (P=0.009), p-selectin (P<0.001), monocyte chemotactic protein type 1 (MCP-1; P=0.012) and the tissue inhibitor of metalloproteinases type 1 (TIMP-1; P=0.044), which in turn showed significant inverse correlations with maximal endothelium-dependent vasodilation. Serum levels of selenium (P=0.012), vitamin C (P=0.038), erythrocyte glutathione peroxidase (P<0.001) and superoxide dismutase (P=0.022) activities were reduced in patients with a more impaired endothelium-dependent vasodilation. Recently diagnosed treatment-naïve essential hypertensives showed a relationship between the endothelial dysfunction, serum markers of inflammation and remodelling and levels of antioxidant substances. These could be potentially helpful markers of high risk in hypertensive patients.