The American College of Cardiology and the American Heart Association last published evidence-based guidelines for the management of ST-segment elevation myocardial infarction (STEMI) in 1999. In mid-2004, in recognition of the evolution and improvement of many of the most basic tenets of clinical management of STEMI since that time, an updated edition of the STEMI guidelines has been published. These guidelines offer many evidence-based recommendations that are pertinent to the out-of-hospital and emergency department care of STEMI patients, including initial evaluation, risk stratification, stabilizing management, and the choice between pharmacologic and mechanical revascularization. These are presented and discussed here.