Levels of catecholamines in blood, excretion of DOPA, dopamine, adrenaline and noradrenaline were determined in 99 hypertensive patients and 22 healthy persons. Walking for an hour and intake of L-DOPA in a dose of 3 mg/kg of body mass were used as functional tests. There was noted an increase in activity and reactivity of the sympathoadrenal system at early stages of the disease with its gradual reduction in the courses of the disease. In all the patients, with the exception of stable hypertensive patients with crisis, there was noted an increase in the biosynthesis of dopamine which is considered as a possible compensatory protective mechanism opposing pressor actions. An increase in the biosynthesis of noradrenaline was found at early stages of the disease in people with hyperreactivity and, in particular, in hypertension with crisis. Stable hypertension was characterized by the tendency to a decrease in the biosynthesis of noradrenaline, more expressed in patients with crisis.