Endothelial dysfunction is one of the causes of progression of atherosclerosis and its clinical manifestation – development of coronary heart disease. The aim of investigation was to evaluate the restoration of endothelial function during 6 months after acute myocardial infarction and to define its relationship to indices of physical load. Bicycle exercise test, determination of endothelial function by index which is defined as increasing the diameter of brachial artery in a response to reactive hyperemia and some indices of oxydant stress and HbA1c were carried out in 81 patients with myocardial infarction. They were examined during acute period, in 3 and 6 months. All patients were divided into two groups: first group (39 patients) received basic therapy, including enalapril, second group (42 patients) in addition to basic therapy received perindopril. At the 1st examination significant disturbances of endothelium function were revealed. The normal reaction of brachial artery in response to reactive hyperemia was registered in 17.5 % pts at 1st, in 33.3 % – at 2nd and in 36.0 % pts during 3rd examination in the first group and in 16.6 %, 32.4 % and 71.1 %, in the second group, respectively. The progressive improvement of endothelial function was observed in 6 months after myocardial infarction in the second group. It was increased from (6.75±0.59) to (11.61±0.78) %. During this period exercise tolerance was increased and level of HbA1c was decreased up to the 3rd examination.