Compelling evidence from randomized clinical trials has established the superiority of an early invasive over a conservative management strategy in patients presenting with non-ST-segment acute coronary syndromes, with a 20% to 40% reduction in recurrent ischemic events in patients undergoing routine early angiography and revascularization when appropriate. Those patients at high risk of death, recurrent myocardial infarction, or ischemia as indicated by elevated concentrations of cardiac troponin, ST-segment deviation, or high clinical risk score derive a greater clinical benefit from early invasive management than patients at lower risk who may be managed effectively with either strategy. Patients who have recurrent ischemia, infarction, hemodynamic instability, or a high-risk stress test should be considered for urgent catheterization regardless of the initial strategy chosen.