BACKGROUND: Depressive symptoms are common among post myocardial infarction (MI) patients and may cause negative impacts on cardiac prognosis. Depression is observed in 35-45% of MI patients. While depression is an independent risk factor for MI, post-MI depression has been shown to be a risk factor for mortality, morbidity, and decreased quality of life in patients. The link between depression and MI is bidirectional in which behavioral and biological mechanisms have been proposed to be involved. The combination of these mechanisms is likely to involve in increasing the risk of mortality. Epidemiological studies have shown the link between depression and increased risk for development of cardiovascular disease, MI, and cardiac mortality. The adverse impact of depression on prognosis of heart disease is preventable with the right treatment. A number of therapeutic approaches including cardiac rehabilitation, social support, cognitive behavioral therapy, and antidepressants have been suggested for post-MI depression. However, due to their adverse effects, tricyclic antidepressants are recommended to be avoided for treating post-MI depression. On the other hand, administering selective serotonin reuptake inhibitors (SSRIs) shortly after MI would lessen their major side effects. Keywords: Myocardial Infarction, Depression, Mortality, Treatment of Depression, Behavioral Mechanisms, Biological Mechanisms.