In patients with acute coronary syndrome (ACS), the periinterventional antithrombotic treatment has become increasingly important for the choice of reperfusion strategy and as an adjunct pharmacological treatment prior, during and after percutaneous coronary interventions (PCI). In NSTE-ACS and early invasive strategy (<48 h), treatment with ASA, clopidogrel and heparin - unfractionated heparin (UFH) preferred - should be initiated as soon as possible. Direct thrombin inhibitors are an alternative to heparin, particularly in the setting of increased risk of bleeding and heparin-induced thrombocytopenia. In highrisk patients, an so-called upstream therapy with glycoprotein IIb/IIIa inhibitors (tirofiban, eptifibatide) is recommended as an adjunct to PCI. In STEMI, primary PCI is the reperfusion therapy of choice and should be supported by early adjunct treatment with ASA, clopidogrel, UFH and glycoprotein IIb/IIIa inhibitors (abciximab, eptifibatide). "Facilitated" PCI with thrombolytics is not recommended because of increased mortality and complication rates.