Background: Acute coronary syndrome (ACS) including ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI), and unstable angina - is an umbrella term for life-threatening situations that occur when the blood supply to the heart is altered due to destabilization of a previously stable atherosclerotic plaque. This alteration hinders the heart muscle from functioning properly and even could lead to death. This study aimed to identify the role of hematological indices in patients with acute coronary syndrome. Methods: This prospective cohort study was carried out on 75 patients; they were divided into 3 groups each of them included 25 patients. Group I represent patients with myocardial infarction (MI), group II represents patients with unstable angina (UA) and control group included 25 subjects. All patients were subjected to complete history taking, clinical examination and routine laboratory investigation. Patients also were subjected to electrocardiography, transthoracic echo Doppler and coronary angiography. Results: Regarding hematological indices for prediction of MI, the ROC revealed: NLR ≥ 4.45 with sensitivity 96%, specificity 92%, Area under the curve 0. 99 and accuracy 94%. RDW ≥ 14.15 with sensitivity 96% specificity 72%, Area under the curve 0.973 and accuracy 84%. PLR ≥ 88.8 with sensitivity 96%, specificity 96%, Area under the curve 0.994 and accuracy 96%. MPV ≥ 9.65 with sensitivity 68%, specificity 52%, Area under the curve 0.646 and accuracy 60%. PDW ≥ 15.15 with sensitivity 96%, specificity 96%, Area under the curve 0.998 and accuracy 96%. Conclusions: There is a high demand for a reliable, accessible, noninvasive, and hematological prognostic marker in ACS, which would identify patients of high cardiovascular risk in secondary prevention and tailor the therapy to their needs. The inflammatory processes play a key role in the development of atherosclerosis, destabilization of atherosclerotic plaques and formation of clots on the plaque surface. There is a significance role of NLR, PLR, PDW, MPV, and RDW in the prognosis of ACS.