Delays in treatment of acute myocardial infarction prevent a substantial portion of patients from receiving maximal benefit from reperfusion therapy. Median delay between onset of symptoms and arrival at the hospital is 2 to 4 hours. Average time between arrival at the hospital and initiation of thrombolytic therapy is 84 minutes. Approximately 50% of patients hospitalized for suspected acute myocardial infarction do not use the emergency medical service system. Delay before treatment can be divided into several components: patient delay, emergency medical service delay, and hospital delay. Factors contributing to delay in each component and possible approaches to decreasing these delays are discussed. The effects of treatment delay on prognosis and future care-seeking behavior of patients hospitalized with suspected acute myocardial infarction are also discussed.