Patients with acute coronary syndrome (ACS) are classified into ST segment elevation myocardial infarction (MI), and non-ST segment elevation MI. An ECG should be obtained on admission and the ST segments are monitored. Patients with ST segment depression have a poorer prognosis when compared with patients with T wave abnormalities. An elevation in biomarkers indicates myocardial necrosis. The preferred biomarker is cardiac troponin (I or T) which has a sensitivity of 100% 6 hours after the onset of MI. Creatine kinase CK-MB is the best alternative when troponin is either unsuitable or not available. This chapter discusses management of ST-elevation ACS using percutaneous coronary intervention (PCI) or fibrinolysis, heparin, antiplatelet therapy, rescue PCI, and surgical revascularization. Non-ST-elevation ACS management strategy is based on low-risk patients, and intermediate and high risk patients. Oxygen and pain relief are given to all the patients along with an antiemetic agent in adjunctive therapy.