Acute Myocardial Infarction is one of the leading causes of death worldwide with the prevalence of approximately three million people. In this study we have investigated Biomarkers like Serum Myoglobin, Creatine kinase MB, Lactate Dehydrogenase in Acute Myocardial Infarction within four hours and after four hours of chest pain. The possible role of Serum Myoglobin as an early indicator of Acute Myocardial Infarction. To determine if there is signicant elevation of Serum Myoglobin less than four hours of Acute Myocardial Infarction and to compare it with other biomarkers of Acute Myocardial Infarction. It is a case control study done among a study population of 80 patients presenting to Emergency department of Government Theni Medical College Hospital with complains of chest pain. The study population was divided into two groups, Cases are 40 patients with chest pain less than 4 hours of duration and Controls are 40 patients with chest pain more than 4 hours of duration. Median Age group of patients in this study was between 51 to 60 years. Sig (2-tailed) test showed statistically signicant difference in all groups namely Serum Myoglobin, Creatine kinase , Lactate Dehydrogenase distribution in cases and controls with p value < 0.05. According to the present ndings in our study, the earliest Serum marker to be elevated in the case of Acute Myocardial Infarction is Serum Myoglobin.As it is not a specic marker, it can be combined with Biomarkers like Creatine Kinase and Lactate Dehydrogenase to indentify AMI at the earliest.