The need to decrease the time to initiation of thrombolytic therapy for acute myocardial infarction (AMI) is described; treatment before hospitalization and in hospital emergency departments (EDs) is discussed. Delay from the onset of AMI symptoms to initiation of thrombolytic therapy can be reduced by improving (1) patient recognition of AMI symptoms and speed in seeking medical assistance and (2) the time that it takes for medical personnel to evaluate the patient's symptoms and to initiate appropriate therapy. Attempts to improve patient response to AMI symptoms have met with limited success. Pre-hospital administration of thrombolytic drugs may be of value, but it has the potential to shorten the time to thrombolytic therapy in only a minority of the affected population because many AMI patients are not transported by the emergency medical services system. The ED is a major focal point for influencing the timing of thrombolytic therapy. Much of what is known about the time sequence of thrombolytic therapy in EDs in the United States comes from organized trials in a small number of centers. Little is known about how often non-ED physicians participate in the decision-making process (either in person or by phone consultation), or how many delays are potentially avoidable. Current evidence suggests that pre-established ED treatment plans and protocols can lessen the time delay for many patients with AMI, especially if paramedics can transmit diagnostic-quality electrocardiograms to the hospital.