Background/Aim. Up-to-date treatment of acute myocardial infarction (AIM) has been based on as early as possible establishment of circulation in ischemic myocardium whether by the use of fibrinolythic therapy and/or urgent coronary intervention which significantly changes the destiny of patients with AMI, but also increases the risk of bleeding. The aim of this study was to compare coronary flow and bleeding complications in patients with acute myocardial infarction with ST-elevation (STEMI) after administration of alteplase or streptokinase. Methods. The study included 254 patients with STEMI. The group I (n = 174) received streptokinase, and the group II (n = 80) received alteplase. We followed frequency of complications such as bleeding and hypotension in the investigated groups of patients, based on the TIMI classification of bleeding, as well as the transience of infarction artery in accordance with TIMI flow. Results. The patients with myocardial infarction after administration of alteplase had statistically significantly higher coronary flow (TIMI- 3), 72.5% as compared to the patients who received streptokinase, 39.2%. Hypotension as complication of fibrynolythic therapy administration occurred in a significantly higher percentage in the group of patients who received streptokinase. There was no statistically significant difference in the appearance of major bleeding in the groups of patients who received streptokinasis and alteplase (6.9% and 7.5%, respectively). Also, there was no difference in the appearance of minor and minimal bleeding among the investigated groups of patients. Conclusion. It was shown that alteplase in a higher number of patients provided TIMI-3 coronary flow as compared to streptokinese. In comparison with streptokinase, a combination of alteplase, enoxaparin and double antiplatelet therapy enabled earlier achievement of coronary flow through previously blocked coronary artery that was more complete (higher frequency of TIMI-3 flow). There were no statistically significant difference in frequency of bleeding, first of all major bleeding, between the groups treated by alteplase and streptokinase.