BACKGROUND: This study aimed to evaluate the effects of streptokinase on left ventricularejection fraction and mortality rate of patients with inferior acute myocardial infarction (AMI)without right ventricular myocardial infarction (RVMI).METHODS: Fifty five consecutive patients with the diagnosis of inferior AMI without RVMI inthe coronary care unit (CCU) of Shariati Hospital in Isfahan were selected for this study.Patients who had a history and/or electrocardiogram (ECG) evidence of previous myocardialinfarction, evidence of bundle branch block, historical or clinical findings of valvular or othernon-coronary heart diseases or heart failure were excluded. Participants were divided into twogroups. Group one (n = 28) had no contraindication for taking thrombolytic therapy and grouptwo (n = 27) had at least one contraindication for this treatment. Patients in group one took1,000,000 units streptokinase for one hour. Three days later, LVEF of all participants wasmeasured by an experienced cardiologist using 2-dimentiona1 echocardiography. Patients werefollowed up until four weeks to assess the mortality rate.RESULTS: One death in the first 24 hours was reported in group one. However, no death wasreported in any group until four weeks after discharge. There was no significant difference inmortality rate during the first 24 hours and four weeks after discharge between the two groups.Mean LVEF in the two groups did not show any significant difference (P = 0.21).CONCLUSION: Probably streptokinase has no effects on one-month mortality rate and LVEF inpatients with inferior AMI without RVMI. Therefore, streptokinase side effects must be takeninto consideration when being administered for this group of patients.Keywords: Inferior Acute Myocardial Infarction, Left Ventricular Ejection Fraction,Streptokinase, Mortality Rate