Acute myocardial infarction is usually diagnosed on basis of chest pain, changes in ECG, and elevation of markers of myocardial injury. The MB isoenzyme of creatine kinase has been the preferred marker for 2 decades. However it can increase in patients with acute or chronic muscle disease without cardiac injury. Many studies have focused on troponin I as a cardiac marker. Troponin, a molecule that binds to the thin filament (actin) of muscle fibres consists of three subunits I, T, and C. This study aimed at comparing immulite troponin I chemiluminescent enzyme immunometric assay to troponin I rapid test in patients with AMI and comparing both assays to CK-MB assay. The study included 37 AMI male patients, 10 healthy controls, patients were divided into 2 groups; group A: 15 patients arrived at the CCU within 5 hours, group B: 22 patients arrived at and after 5 hours. CK-MB had a sensitive of 26.7 % in group A, 86.4 % in group B; specificity 90% and accuracy 68%, rapid troponin I test had a sensitivity of 0% in group A 100% in group B; specificity 100% and accuracy 68%. Immulite troponin I assay had a sensitivity of 40% in group A, 100%in group B, specificity 100% and accuracy 80.9%. It was recommended to use the rapid troponin I test at and after 5 hours from onset of symptoms.