Background: ST-elevation myocardial infarction (STEMI) is one of the leading causes of mortality and morbidity worldwide. However, survival after acute STEMI has considerably improved due to increasing symptom recognition, accurate diagnosis and effective timely reperfusion. This study aimed to investigate the relation between the level of oxidative stress markers and coronary no-reflow after primary percutaneous coronary intervention for patients with acute myocardial infarction. Patients & Methods: This prospective cohort study included 90 patients admitted with acute STEMI at cardiovascular medicine department Naser Institute hospital, during the period from June 2018 till 12 months. Patients were divided into 2 groups according to the post primary PCI thrombolysis in myocardial infarction (TIMI) flow score into: Group I: 45 patients with noreflow phenomenon. Group II: 45 patients with TIMI flow ≥ 2 after primary PCI. They all underwent primary PCI within 24 hours of presentation. Results: This study showed increased concentrations of Malondialdehide (MDA) in the circulation of patients with no-reflow indicating increased lipid peroxidation which could be attributed to a deficiency of antioxidant defense mechanism. In group I, pt with coronary no-reflow MDA level ranged from 2.8-4.5 nmol/mL with mean 3.9±1.5 nmol/mL, while in group II control group, MDA level ranged from 1.1 -2.1 nmol/mL with mean 1.55±0.4 nmol/mL, there was statistically significant difference between the two groups (P value<0.004). Conclusions: no-reflow phenomenon after primary PCI can be predicted using the oxidative stress markers.