Background: Large numbers of patients are faced with mechanical complications after myocardial infarction (MI). Such complications occur when the patient does not receive immediate treatment, leading to adverse consequences and even death. The present study was conducted to determine the short- and long-term prognoses of this group of mechanical complications. Method: The present case-series study recruited all patients (N = 88) who had a diagnosis of cardiac mechanical complications following acute MI at Rajaie Cardiovascular, Medical, and Research Center between 2005 and 2011. The short-term prognosis of the study population was recorded before discharge (hospital mortality rate), and the patients were followed up 6 months later through phone calls. The results and 6 months’ prognosis—including mortality, survival rate, and hospitalization—were recorded again. Results: The mean age of the study population was 70.50 ± 10.23 years (31–95 y) and 46.6% were male. The most common complications were apical ventricular septal rupture (VSR) (67.1%), ventricular free-wall rupture (14.8%), basal VSR (7.9%), pseudoaneurysm (4.5%), VSR with pseudoaneurysm (3.4%), and papillary muscle rupture (2.3%)–respectively. The rate of death caused by mechanical complications was 4.61%. The rate of re-hospitalization was 6.8%. In this study, 36.3% of the patients died after reconstructive surgery and 34.1% of them died after medical treatment in the hospital. The 6-month survival rate of the patients was 34.1%. Conclusions: The mechanical complications of the heart occur mainly in women and older patients. In this regard, apical VSR and ventricular free-wall rupture are the most common complications. However, in the case of timely medical interventions such as reconstructive surgery, the survival rate improves significantly. (Iranian Heart Journal 2017; 18(4):21-28)