Background: Acute treatment of ST elevation myocardial infarction (STEMI) is restoration of myocardial perfusion by recanalization of the occluded vessel. Objective: The aim of the present study is to detect no reflow post primary percutaneous coronary intervention (PCI) in young STEMI patients and to correlate clinical, electrocardiogram, angiographic and procedural variables with no reflow. Patients and methods: This Cohort study was conducted in the Cardiology Department, Faculty of Medicine, Zagazig University on 106 young patients with acute myocardial infarction treated with PPCI during the period from January 2021 to April 2022. The patients were divided into 2 groups according to myocardial blush; Group (I) which included 80 patients with normal flow, and Group (II) which included 26 patients with No reflow. Results: We found that No significant difference between the 2 studied groups regarding Initial Thrombolysis in Myocardial Infarction (TIMI) flow 0 or 1. The admission EF was significantly lower among the No Reflow Group and the no reflow group significantly associated with major adverse cardiovascular events (MACE), mortality, smoking, low EF and anterior wall myocardial infarction (AWMI) were independent predictors for no reflow. Conclusions: No reflow in young patient with STEMI could be attributed to novel predictors such as Smoking, low EF and AWMI. This phenomenon was associated with MACE and higher mortality.