Coronary artery disease (CAD), including its most severe complication, myocardial infarction (MI), is the leading cause of death in the industrialized world. As the most serious clinical manifestation of CAD, MI is the condition of irreversible necrosis of the heart muscle that results from prolonged ischemia. Approximately 90 % of MI results from the formation of an acute thrombus that obstructs an atherosclerotic coronary artery. Coronary artery disease (CAD) is a major cause of mortality and morbidity in the general population worldwide. CAD has a complex etiopathogenesis and a multifactorial origin. Osteoprotegerin (OPG) that is a glycoprotein belonging to the tumor necrosis factor (TNF) receptor superfamily, functions as a dummy receptor for both the TNF-linked apoptosis-inducing ligand (TRAIL) and the nuclear factor κ-B ligand receptor (RANKL). These elevated OPG levels are linked to a wider variety of coronary artery atherosclerotic lesions and an increased mortality risk. The relationship between serum OPG (osteoprotegerin) level with the development and progression of CAD among patients is not clear. It may be potential predictor of CAD among patients and may be used in the treatment of CAD.