Unstable angina (UA) and non-ST-segment elevation myocardial infarction (NSTEMI) refer to a spectrum of acute severe cardiac disorders characterized by myocardial oxygen demand and supply mismatch, caused by atherosclerotic coronary artery disease. Patients presenting with acute coronary syndromes represent a major medical problem, accounting for 2.5 million hospitalizations and 500000 deaths annually in the United States alone. Of these, 1.5 million have a final diagnosis of UA, and myocardial infarction (ST-segment and non-ST-segment elevation) accounts for the remaining 1 million. The management of UA/NSTEMI presents a challenge to the cardiologist because treatment strategies continue to evolve. A number of trials have now assessed the safety and efficacy of early revascularization strategies in the treatment of patients with UA/NSTEMI, whereas others have focused on pharmacologic adjunctive therapy. An optimal single strategy encompassing most patients' needs is not clear. This review focuses on the revised American College of Cardiology/American Heart Association guidelines for the management of patients presenting with UA/NSTEMI.