Background:Despite recent advances in interventional equipment and techniques, the angiographic no-reflow and slow flow phenomenons occurs in a considerable number of patients undergoing primary percutaneous coronary intervention (PCI). We investigated the clinical, electrocardiographic, pre procedural finding that could predict slow flow/ no reflow in ST-segment Elevation Myocardial Infarction (STEMI) patients treated with PCI, also to detect predictors and impact of slow flow/ no reflow during hospital stay and short term outcome of such patients Aim: To identify the clinical, electrocardiographic, pre procedural finding that could predict slow flow/ no reflow in STEMI patients treated with PCI and to determine predictors of adverse clinical events during hospital stay and short term in slow flow /no reflow group. Patients and Methods: Thestudy included 72 patients who were divided into 2 groups, group I with slow flow/no reflow and group II with normal flow. All of them were subjected to follow up for 3months after PCI. Results:Regarding ECG there was a statistically significant increase in all ECG parameters between patients with no reflow before PCI except STR there was significant decrease between patients with no reflow before PCI.After applying multivariate analysis QRST before PCI, RWPT before PCI still significant predictors for occurrence of no reflow after PCI.Our study shows a statistically significant difference in short term outcome occurred on follow up after 3 months between both studied groups.QRST parameter before and after PCI and RWPT before PCI were statistically significant predictors for short term impact but there was no statistically significant difference among both studied groups regarding angiographic findings of the lesion