Unstable angina is the most frequent acute coronary syndrome. Risk stratification to predict coronary morbidity and mortality and the risk of major hemorrhage is the key element of the medical approach. Combined antithrombotic therapy (including aspirin, clopidogrel, low-molecular-weight heparin and, possibly, glycoprotein IIb/IIIa receptor antagonists) has led to a substantial reduction in major coronary events; tolerance is good because the treatment is brief and aggressive. Combined antithrombotic therapy also increases the benefit of early invasive strategies including coronary angiogram with stent-based percutaneous coronary angioplasty.