Hypertensive crisis is a sudden rise in blood pressure with accompanying clinical symptoms. The disease is extremely rare in small children and is always a complication of secondary hypertension.3-year-old boy (spontaneous delivery, 37 week of gestation, birth weight 2170g, 10 AS, unremarkable family history) was admitted to a hospital because of weight loss (1.5 kg, i.e. approx. 15% in 6 months), anorexia, abdominal and limb pain and lethargy. On admission, very high blood pressure values (190/150 mm Hg), lean subcutaneous tissue, frequent blinking, height 88 cm (<3c), body weight 9.5 kg (<3c). In additional tests: blood morphology, parameters of renal function, ions, gasometry, catecholamine urinary excretion, steroid profile and daily cortisol profile were within normal limits. Elevated plasma renin activity was found. In imaging studies kidneys, adrenal glands and renal arteries were normal. Normotension was not obtained on two antihypertensive drugs - metoprolol and amlodipine. In angio-CT tortuous right vertebral artery, extending to the left on the anterolateral surface of the medulla oblongata - possible compression of the vessel of the left side of medulla - was found. Diagnosis of neurovascular conflict was made. The patient was consulted by neurosurgeon who declare no possibility of surgical treatment of anomalies. In the treatment, according to the literature, a drug blocking the renin-angiotensin-aldosterone-enalapril system was used, which normalized blood pressure. At the same time, intensive nutritional treatment was used. Resolution of symptoms and weight gain was observed. In further follow-up patients' parents withdrew enalapril lawlessly, which did not lead to recurrent rise in blood pressure. The latter may suggest other, transient cause of hypertensive crisis e.g. intoxication.Severe hypertension in pediatric patients can give symptoms as weight loss and behavioral disorders. In the diagnostic of hypertensive crisis in children, neuroimaging studies and toxicological tests should be performed.