Acute coronary syndromes (ACS), such as myocardial infarction and unstable angina, are leading causes of death in developed countries. The risk of recurrent adverse events, rehospitalization, and death remain high in the weeks to months following ACS. Large secondary prevention trials have shown that the initiation of statin therapy within 3-6 months after hospitalization for ACS decreases the risk of recurrent cardiovascular events and death. Although the precise mechanisms behind these clinical benefits are unknown, data from human and animal studies have implicated statins in inflammatory response modulation, plaque stability, thrombus formation, and endothelial function. Several observational studies have demonstrated cardiovascular mortality and morbidity benefits in patients with ACS who were placed on statins within hours to days of their event. Three recent prospective controlled trials confirmed these benefits and demonstrated that moderate doses of statins are safe when used in patients with ACS. We recommend the initiation of statin therapy in all ACS patients prior to hospital discharge.