Selection of a thrombolytic agent for an individual patient depends on the baseline clinical characteristics of the patient, in particular any risk factors for stroke and the time from pain onset to presentation. Another important factor is consideration of cost. The GUSTO trial showed that administration of accelerated tissue plasminogen activator (TP A) within 6 hours of the onset of pain resulted in a reduction in mortality rates across all subgroups when compared with administration of streptokinase. The greatest benefit was seen in those patients at greatest risk. Streptokinase may be considered the agent of choice in patients with risk factors for stroke, patients treated more than 6 hours from symptom onset, and patients in whom the incremental benefit of TP A is small and the cost/benefit ratio is likely to be high.