Cardiac troponins are sensitive and specific markers of myocardial injury. The troponin concentration can be thought of as a quantitative measure of the degree of injury sustained by the heart, however, it provides no information on the cause of injury or the mechanism of troponin release. Conventionally, the cardiac troponins have been used for diagnosis of acute myocardial infarction in humans and have become the gold standard biomarkers for this indication. They have become increasingly recognized as an objective measure of cardiomyocyte status in both cardiac and noncardiac disease, supplying additional information to that provided by echocardiography and ECG. Injury to cardiomyocytes can occur through a variety of mechanisms with subsequent release of troponins. Independent of the underlying disease or the mechanism of troponin release, the presence of myocardial injury is associated with an increased risk of death. As increasingly sensitive assays are introduced, the frequent occurrence of myocardial injury is becoming apparent, and our understanding of its causes and importance is constantly evolving. Presently troponins are valuable for detecting a subgroup of patients with higher risk of death. Future research is needed to clarify whether troponins can serve as monitoring tools guiding treatment, whether administering more aggressive treatment to patients with evidence of myocardial injury is beneficial, and whether normalizing of troponin concentrations in patients presenting with evidence of myocardial injury is associated with reduced risk of death.