Acute coronary syndromes remain the leading cause of mortality in the United States and represent an enormous cost to the health care system. Despite decades of investigation into the diagnosis of acute myocardial infarction (MI), the diagnostic process is still quite complex because the majority of patients with chest pain fall in the low or medium risk category with atypical symptoms and nonspecific electrocardiogram (ECG) changes. Cardiac biochemical markers play an important role in helping physicians make the diagnosis and stratify the risk to patients. However, the ideal cardiac marker and the best diagnostic approach to patients with chest pain in the Emergency Department (ED) remain elusive. Currently, among many cardiac markers, cardiac troponin I seems the most cardiac-specific in the diagnosis of acute MI. This article is focused on reviewing the characteristics of different cardiac markers and comparison of their usages in the diagnosis of acute MI. However, since this field is large and rapidly expanding, it is impossible to cover every aspect of cardiac markers. As the search for the most efficacious, specific and cost-effective means to approach patients with chest pain continues, further prospective, randomized, multicenter trials are needed to confirm the value of troponins and other diagnostic strategies in the early diagnosis of acute MI.