Nineteen patients with acute myocardial infarction presenting within 6 1/2 hours of onset of chest pain were given intravenous rt-PA (Actilyse) at a dosage of 10 mg i.v. bolus followed by 3 hours drip infusion up to a total dose of 100 mg. The results of this therapeutic regimen were reviewed in order to determine if thrombolytic therapy using recombinant tissue-type plasminogen activator (rt-PA) can reduce in-hospital mortality in patients with acute myocardial infarction without producing major bleeding tendencies There were fourteen patients who were given rt-PA from less than 1 hour to 4 hours after the onset of symptoms. These patients were relieved of chest pain within 10 minutes to 2 hours. The other three patients who were given rt-PA 6 hours after symptom onset were relieved of chest pain after 4 hours to 7 hours. There were two deaths, both were in cardiogenic shock on admission. They were given rt-PA 6 hours after the onset of chest pain. These two conditions namely, cardiogenic shock and delayed administration of rt-PA, when present, can almost always predict failure of thrombolytic therapy. It was concluded that rt-PA administration in acute myocardial infarction revealed a trend towards reduced mortaliy at 21 days. Bleeding tendencies in 5 patients were all minor which did not require blood transfusion.