A comparative study of the myocyte nucleolar organizer activity (NOA) was performed on silver-stained myocardium from 6 patients who had died from the hypertension disease and 7 others patients with secondary renal hypertension non-complicated by severe coronary atherosclerosis and heart failure. In the first group, positive correlations between NOA of cardiac cells and the level of maximal diastolic pressure (r = 0.8, p less than 0.028), wall thickness of the left ventricle (r = 0.8, p less than 0.028) as well as myocardial weight (r = 1.0, p less than 0.001) were found. In the second group, on the contrary, there was a pronounced negative correlation between NOA of the myocytes and myocardial weight (r = -0.86, p less than 0.005) which may be explained partially by a primary metabolic myocardial deficiency in such patients.