BACKGROUND The aim of this study was to examine the association between left ventricular ejection fraction (LVEF) and incidence of depression following the myocardial infarction (MI). METHODS In a prospective study, 176 patients aged 32-84 years with the mean age of 56 years (SD = 10.05) with a definitive diagnosis of myocardial infarction and admitted to one of the coronary care units (CCU) of Isfahan during April to August 2006 were selected through consecutive sampling method. The demographic and medical characteristics were collected by their medical record and also the results of the LVEF assessment of the patients were obtained through echocardiography or angiography following the myocardial infarction. Thereafter, the patients were given Beck Depression Inventory for the primary care (BDI-PC) in three months after myocardial infarction. The collected data were analyzed during the hospitalization and follow-up periods using logistic regression method. RESULTS The findings indicated that left ventricular dysfunction identified by the Left ventricular ejection fraction index was significantly correlated with depression three months after the myocardial infarction (P < 0.01). In addition, the exploratory model (which only includes LVEF variable) had the predictive validity of 64.8% with 55.7% sensitivity and 72.1% specificity. CONCLUSION Left ventricular dysfunction is associated with increased risk of depression following the myocardial infarction.