Aim. To evaluate the clinical and pathogenetic value of nitric oxide metabolites measurement in the blood of patients with bronchial asthma and essential hypertension. Methods. The study included 91 patients. Three groups were identified: patients with bronchial asthma (30 patients, group 1), patients with bronchial asthma in combination with essential hypertension (31 patients, group 2), and patients with essential hypertension (30 patients, group 3). Measurement of the level of total nitric oxide metabolites in patients’ blood was performed with the use of spectrophotometric method in light spectrum based on Griess reaction. Results. The median level of nitric oxide metabolites had the highest value in the blood of patients with bronchial asthma and accounted for 75.6 [70.4; 80.8] umol/L. Level of nitric oxide metabolites in the blood of patients with bronchial asthma in combination with essential hypertension and patients with essential hypertension was lower, accounting for 72.4 [66.2; 81.2] and 60.0 [54.6; 62.7] umol/L respectively (p