HMG Co-A reductase inhibitors(statins) have been shown, in three large randomized trials, to decrease adverse cardiac events in patients with clinically evident coronary artery disease. All of these trials have excluded patients with an acute coronary syndrome within the three months prior to enrollment. Statin therapy is thought to stabilize coronary plaque and decrease the risk of plaque rupture. Statins have been shown to quickly reduce levels of LDL-C in addition to altering systemic inflammatory responses, improving endothelial function, and reducing platelet aggregation and activation. These mechanisms are potentially beneficial in the setting of acute coronary syndromes, a time of profound plaque instability. There is a growing body of evidence supporting the early initiation of statin therapy in the setting of acute coronary syndromes. This paper reviews the available data from randomized-controlled trials and observational studies evaluating the effect of early statin initiation during, or soon following, an acute coronary syndrome.