The authors examined dynamicaly from the third day to the third month the activity of enzymes, participating in glycolysis (ALD, PK, LDH), pentosemonophosphate shunt (G6P-DH), citric cycle (MDH, INDH) in the myocardium of rats with hypertension, induced by the method of Selye, modified by Kolarova. There were phase changes in enzymatic activity in the myocardium, manifested at the first stages by lowering (LDH, ALD, INDH) or elevation (MDH, PK, G6-DH). The activity of all examined enzymes was over that of the control group on the thirteenth day, while there were also oscillations on the nineteenth day. Only the actimity of G6-DH revealed a progressive elevation during the whole experimental period. The changes in the enzymic activity of the myocardium at the first stages were interpreted as a sign of nonspecific adaptation to the changed conditions of heart activity. The later changes were manifestations of the disturbances at various metabolic links, which were unevenly involved in the processes of myocardial hypertrophy.