Background: The optimum treatment for ST-elevation myocardial infarction (STEMI) is rapid reperfusion with primary percutaneous coronary intervention (PCI). Myocardial tissue hypoperfusion persists in many patients after initial PCI despite the epicardial coronary circulation achieving restored patency. Therefore, our study aimed to assess the relationship between simple electrocardiographic (ECG) parameters and reperfusion in STEMI. Patients and methods: A cross sectional study was carried out one hundred STEMI patients subjected to 12 leads ECG before and sixty minutes after (PPCI) to assess QRS duration, T wave peak to end terminal(TPE) interval. Results: One hundred cases were classified into two groups according to MBG (myocardial blush grade), group I (30) cases (Impaired flow MBG<3) and group II (70) cases (successful flow MBG=3). Significant longer duration of pre PCI QRS, post PCI QRS, pre corrected PCI TPE, post PCI TPE, post PCI corrected TPE were in group I. Conclusion: Prolonged pre QRS duration 86ms and maximal ST elevation in mm were significant predictors of no reflow in STEMI treated with primary PCI