Mitral regurgitation may develop due to left ventricular (LV) remodeling within 3 months following acute myocardial infarction (AMI) and is called ischemic mitral regurgitation (IMR). Ischemic preconditioning (IPC) has been reported as the most important mechanism of the association between prior angina and the favorable outcome. The aim of this study was to investigate the effect of prior angina on the development and severity of IMR at 3rd month in patients with ST elevation MI (STEMI). Fourty five (45) patients admitted with STEMI and at least mild IMR, revascularized by PCI were enrolled. According to presence of prior angina within 72 h before STEMI, patients were then divided into two groups as angina (+) (n:26; 58%) and angina (-) (n:19; 42%). All patients underwent 2D transthoracic echocardiography at 1st, 3rd days and 3rd month. IMR was evaluated by proximal isovelocity surface area (PISA) method: PISA radius (PISA-r), effective regurgitant orifice area (EROA), regurgitant volume (Rvol). LV ejection fraction (EF %) was calculated by Simpson's method. High sensitive troponin T (hs-TnT), creatine phosphokinase myocardial band (CK-MB) and N-terminal pro-brain natriuretic peptid (NTpro-BNP) levels were compared between two groups. Although PISA-r, EROA and Rvol were similar in both groups at 1st and 3rd days, all were significantly decreased (p = 0.012, p = 0.007, p = 0.011, respectively) and EF was significantly increased (p< 0 .001) in angina (+) group at 3rd month. NTpro-BNP and hs-TnT levels at 1st day and 3rd month were similar, however CK-MB level at 3rd month was found to be significantly lower in the angina (+) group (p = 0.034). At the end of the 3rd month, it was observed that the severity of IMR evaluated by PISA method was decreased and EF increased significantly in patients who defined angina within 72 h prior to STEMI, suggesting a relation with IPC.