We carried out complex examination of 68 adolescents aged 11-17 years with primary obesity which in addition to assessment of clinical-anamnestic, laboratory data and functional parameters of cardiovascular system included registration of reaction of brachial artery endothelium to reactive hyperemia. Vascular endothelial dysfunction (VED) was found in 66% of obese teenagers. Obesity in adolescents with VED was characterized by aggravated course with higher fat mass index (36.8 +/- 4.39%) and prevalence of hypothalamic (42%) and metabolic (8.8%) syndromes. Stable arterial hypertension (AH) found in 37% of examined adolescents was 1.5 times more often registered in those with VED. We distinguished 4 groups of adolescents with various degree of risk of development of cardiovascular disorders: with stable AH and VED (group I), with stable AH and normal function of vascular endothelium (group II), with normal or labile arterial pressure with VED (group III), with normal or labile arterial pressure with normal function of vascular endothelium. It is expedient to supplement examination of obese adolescents with assessment of the state of vascular endothelium aiming at determination of degree of risk of development of atherosclerosis and/or stable AH.