We aimed to define factors predicting mortality in patients having ST elevation myocardial infarction (STEMI) who had Primary Percutaneous Coronary Intervention (PCI) in our setting.This is a prospective study on patients presenting to the emergency department with STEMI who underwent PCI during a 12-month period. Physiological parameters were calculated using the vital signs and age of patients. Time-based factors in the institutional protocol were collected. Univariate analysis was performed to define significant factors that affected mortality. Significant factors were then entered into a logistic regression model. Factors significantly affecting mortality were defined. Receiving operating characteristic curve was applied to define the best predictors of mortality.A total of 167 consecutive patients were studied; 128 (76.6%) were males. The mean (SD) age of the patients was 61.9 (12.8) years. The logistic regression model showed that significant factors were age (P=.002), Modified Shock Index, MSI (P=.028), systolic blood pressure (P=.028), and time between consultation and activation of catheter laboratory (P=.047). The cut-off points with best prediction of mortality were age of 71.5 years, systolic blood pressure of less than 95 mmHg, MSI of 0.85, and a time more than 3.5 minutes between consultation and activation of catheter laboratory.Our study shows that significant predictors of 30-days mortality of STEMI were age, systolic blood pressure on presentation, MSI, and the time between consultation and catheter laboratory activation. Improving prehospital resuscitation and activation of the catheter laboratory by emergency physicians may reduce mortality in our setting.