Thirty-two patients with ischemic stroke of various localization were examined. The method of tetropolar rheography was used; 300 tetrapolar rheograms were recorded. The patients were examined before, immediately after, and 2--3 hours after the hyperbaric oxygenation session; the haemodynamics were studied several times during the course. On the grounds of the study carried out, the authors conclude that in most patients the first HBO sessions cause a general vasoconstricting effect and lead to a decrease in the cardiac output; the next sessions normalize the initially abnormal hemodynamics; the HBO sessions hardly cause any changes in arterial pressure, in patients with vertebrobasilar pathology, however, a mild elevation of systolic and mean pressure was recorded after the sessions; hyperbaric oxygen reduces the rate of cardiac contractions by 9% irrespective of the initial pulse rate.