Long-term follow-up of 98.3% of the 11,712 patients recruited in the GISSI trial of intravenous streptokinase (SK) in acute myocardial infarction has shown persistence of the beneficial effect observed during the hospital phase. At 12 months a significant difference in mortality was seen in the whole population (17.2% in SK group versus 19.0% in controls, p = 0.008, relative risk 0.90), and in the 0-3 and 3-6 h groups (relative risks 0.89 and 0.87, respectively). For most of the other strata according to which the trial population has been analysed, the magnitude and the direction of the effects were also substantially the same as those recorded in the hospital phase. SK thrombolysis should be considered among the recommended treatments of the acute phase, at least up to 6 h from onset of myocardial infarction.