Abstract The need for a rapid and reliable diagnosis of myocardial infarction is crucial. Initial efforts focused on clinical assessment and electrocardiography, but over time it became clear that they are often nondiagnostic. Therefore, clinicians now rely heavily on cardiac biomarkers. Guidelines call for the routine assessment of cardiac biomarkers for the diagnosis of myocardial infarction. The cardiac biomarkers cardiac troponin and creatine kinase are reviewed in this chapter: cardiac troponin, creatine kinase, as are their use in acute myocardial infarction diagnosis and prognosis.