Chest pain not only accounts for almost 1 in 10 emergency department (ED) visits but constitutes the source of more malpractice dollars than any other chief complaint. Problems in accurately diagnosing serious causes of chest pain include atypical histories, lack of pertinent physical findings, and limited sensitivity and specificity of current diagnostic tests. Areas holding promise include the expanded use of the ECG, new and improved technology for the detection of serum markers of myocardial injury, the extension of noninvasive testing to the ED setting, and the adoption of clinical prediction rules to estimate probabilities of various causes of chest pain.