Patients suffering from non-valvular atrial fibrillation and presenting with an acute coronary syndrome require special attention with regard to antithrombotic therapy. Current guidelines recommend use of oral anticoagulation for almost all of these patients, the optimal antithrombotic strategy, however, has still to be defined. As with the use of any antithrombotic drug, clinicians need to balance the risks of ischemic stroke and thromboembolism, recurrent cardiac ischemia and/or stent thrombosis, and bleeding and haemorrhagic stroke.