Unstable angina (UA) and non-ST-segment elevation myocardial infarction (NSTEMI) represent two common, closely related acute coronary syndromes with potentially high morbidity and mortality. Integration of information from the history, physical exam, electrocardiogram, and cardiac biomarkers is used to formulate both the diagnosis of UA/NSTEMI and the overall assessment of patient prognosis and risk. Early diagnosis and risk stratification of patients with UA/NSTEMI enable the physician to initiate timely, appropriate treatment. (There is strong clinical evidence supporting the tailoring of specific therapies to the risk profile of the patient.) In recent years, powerful new medical and invasive therapies have been developed. Pharmaceutical agents for UA/NSTEMI may be broadly grouped into one of three categories: anti-ischemic, anti-platelet, and anti-thrombotic agents. Standard therapy for UA/NSTEMI has commonly included oxygen, aspirin, nitrates, morphine, beta-blockers and heparin. Potent new anti-platelet agents, including inhibitors of platelet adenosine diphosphate and glycoprotein IIb/IIIa receptors, play important, expanding roles in the management of these syndromes. Low-molecular-weight heparins have been shown to be an effective alternative to unfractionated heparin in their treatment. Major advances in invasive techniques and devices over the last decade include revascularization with percutaneous coronary intervention and drug-eluting intracoronary stents. Strong interest exists in studying the potential benefits and risks associated with an early invasive therapeutic strategy rather than an aggressive medical regimen for patients with UA/NSTEMI. As new treatments are rapidly added to our growing arsenal of management options, clinicians are constantly challenged with incorporating complex new information and guidelines into their practices in a timely fashion. To assist clinicians with this challenge, this article will review the evidence to support the use of current therapeutic options for UA/NSTEMI, with an emphasis on summarizing the most recent clinical guidelines jointly published by the American College of Cardiology and the American Heart Association.