Background: Coronary artery disease is a major cause of morbidity and mortality worldwide. A major health concern in the developing countries is opioid addiction, which has controversial cardiovascular side effects. We aimed to investigate whether Myocardial Infarction (MI) and its risk factors are associated with morphine dependency in the Iranian population. Methods: Electronic databases, including PubMed, Medline, Scopus, SID, Element, and Magiran were searched to find published articles including the keywords morphine, coronary artery disease, hypertension, hyperlipidemia, and diabetes mellitus. Results: Twelve studies involving 25,800 people were included in this systematic review and metaanalysis. Morphine dependency was significantly associated with MI with an adjusted odds ratio (AOR) of 2.28 (95%CI=1.26-4.11). It neither has significant associations with hypertension (AOR=0.952; 95%CI=0.696-1.301) nor diabetes (AOR=0.895; 95%CI=0.644-1.246). Morphine dependency also had no significant association with hyperlipidemia with a Crude Odds Ratio (COR) of 0.906 (95%CI=0.786-1.045). Conclusion: Morphine dependency was significantly related to MI, but its risk factors were not significantly associated with morphine dependency. The increasing prevalence of opioid abuse in developing countries may be a reason for the growing incidence of MI in younger ages and individuals with no risk factors. Besides, physicians should consider the presence of impurities in morphine-based opioids and their possible effects on health.