Osteoprotegerin is a glycoprotein contributing to the regulation of bone rebuilding. It has been documented that osteoprotegerin regulates the activity of osteoclasts by blocking the interaction between the receptor, activator nuclear factor kappa B (RANK) and its ligand (RANKL). Osteoprotegerin, by blocking the connection between RANKL and its receptor (RANK), inhibits the maturation of osteoclasts and osteoclastogenesis and because of this, it inhibits the osteolytic processes. The participation of osteoprotegerin in regulating the function of immune system cells has also been confirmed. More and more studies confirm, that osteoprotegerin is associated with cardiovascular diseases. In many studies it has been confirmed that high plasma concentration of osteoprotegerin and low concentration of TNF – related apoptosis inducing ligand (TRAIL) and high OPG/TRAIL ratio are predictors of a poor prognosis in patients with myocardial infarction. High plasma concentration and high OPG/TRAIL ratio in the acute phase of myocardial infarction are mainly prognostic indicators of adverse left ventricular remodelling and the development of postinfarction heart failure. In a group of patients with high plasma concentration of osteoprotegerin in the acute phase of myocardial infarction, it has also been established that there are a lower number of mesenchymal stem cells (MSC) recruited from bone marrow and circulating in peripheral blood. Pathogenic mechanisms which involve osteoprotegerin and which are responsible for both postinfarction left ventricular remodelling and prognosis after myocardial infarction are being researched amid great excitement. This is mainly because it offers the possibility of identifying the defence mechanisms which protect the left ventricular against adverse remodelling after myocardial infarction. This would offer us the possibility of using osteoprotegerin not only as a prognostic marker in cardiovascular diseases but also as a potential therapeutic target in cardiovascular diseases. This review presents the current knowledge about this.