New biochemical markers for myocardial cell injury that provide new diagnostic options have recently been introduced. The analytical sensitivity and specificity of the traditional creatine kinase and creatine kinase MB activity measurements have been improved by monoclonal anti-creatine kinase MB antibodies. An assay for creatine kinase MB subforms has proven helpful in early detection of myocardial infarctions and has the potential to guide admissions to coronary care units. Myoglobin was shown to add valuable information to the presenting electrocardiogram in patients with suspected myocardial infarctions. Early assessment of the success of reperfusion therapy can be performed by serial measurements of various markers. The more cardiospecific troponins appear to be advantageous parameters with which to quantify infarct size and to disclose perioperative myocardial infarctions. Troponin T detects minor myocardial cell injury in patients with unstable angina and allows stratification of patients into high- and low-risk categories. Future studies must define the role of the improved diagnostic markers on patient management and costs.