Material and method The investigation included 48 hypertensive children (average age 14,2) suffering from obesity and overweight. There was determined the level of serum homocysteine and nitric oxide. Arterial hypertension was established by the percentile method depending on age, sex and waist. Grade of the obesity was appreciated by Ketle index (IMC) according to the age and percentile method. Homocysteine was determined by the fluid chromatography method with the change of ions. The optimal level of the homocysteine was considered 4–9 mmol/L according to NHANES (2003). Nitric oxide was determined by the spectrophotometric method. Control group included 25 healthy children with the average age 14 years.

Results The value of the homocysteine at the investigated children varied from 11 mmol/L to 28 mmol/L, showing significantly higher level as compared with the norms of the age. Analyses of the nitric oxide level showed significantly reduced level (75,60 mmol/L) in comparison with the control group (95,28 mmol/L)

Conclusion The results of the investigation showed significantly increased level of the homocysteine and reduced one of the nitric oxide at hypertensive children with overweight as compared to the control group, that proves the presence of the endothelial dysfunction at such category of patients.