Background/Aim. Most patients with acute myocardial infarction with ST-segment elevation (STEMI) are still treated with pharmacological reperfusion, which is not always successful. That is the reason for searching possibilities for a better success of reperfusion with adding new antiplatelet drugs. The aim of this study was to investigate weather addition of clopidogrel as a second antiplatelet drug, improves the patency of the infarct-related artery after STEMI. Methods. We prospectively enrolled 65 patients, 29−72 years old, hospitalized due to the first STEMI within 6 hours after the onset of a chest pain. They were treated with a fibrinolytic agent (streptokinase or tissue plasminogen activator − tPA), aspirin, and low molecular heparin (enoxaparin). A group of 50 patients, beside this therapy, received clopidogrel. Coronary angiography was performed between 5th and 10th day of hospitalization to assess for late patency of the infarct-related artery. Infarct-related artery was considered as patent if thrombolysis in myocardial infarction (TIMI) flow grade was 2 or 3, and as occluded if TIMI flow grade was 0 or 1. Results. In the group of patients who received double antiplatelet therapy (aspirin and clopidogrel), infarct-related artery was occluded in 3 cases (6%); in the group of patients without clopidogrel, infarct-related artery was occluded in 4 patients (26.7%), p < 0.05. There were less frequency of postinfarction angina (6% vs 13.3%), and rarer necessity for rescue percutaneous coronary intervention (4% vs. 13.3%) in the first group, but without statistical significance. Conclusion. Adding of clopidogrel to the standard reperfusion pharmacotherapy, as a second antiplatelet drug, increases the number of patients with patent infarct-related artery and the success of reperfusion.