Magnesium has properties of myocardial cytoprotection, the pathophysiological explanations of which in acute myocardial infarction include prevention of arrhythmia, antiplatelet effect, prevention of reperfusion injury, and coronary vasodilation. Although several studies have evaluated the role of magnesium administration in patients with acute myocardium infarction, the clinical impact of such a therapy in this condition has been controversial, largely as a result of conflicting data from randomized controlled trials. The data available to date do not favor the routine administration of intravenous magnesium in patients with myocardial infarction, but this should not preclude magnesium administration to replenish low serum magnesium concentrations or use of magnesium sulfate for treatment of torsade de pointes in patients with myocardial infarction.