Background: Stroke is the most feared complication of thrombolysis for acute myocardial infarction because of the resulting mortality and disability. We analyzed the incidence, timing, and outcomes of stroke in an international trial. Methods and Results: Patients were randomly assigned to one of four thrombolytic strategies. Neurological events were confirmed clinically and anatomically and were adjudicated by a blinded committee. Stroke survivors, categorized by residual deficit and disability, assessed their quality of life with a time trade-off technique. Multivariable regression identified patient characteristics associated with intracranial hemorrhage. Overall, 1.4% of the patients had a stroke (93% anatomic documentation). The risk ranged from 1.19% with streptokinase/subcutaneous heparin therapy to 1.64% with combination thrombolytic therapy (P=.007). Primary intracranial hemorrhage rates ranged from 0.46% with streptokinase/subcutaneous heparin to 0.88% with combination therapy (P<.001). Of all strokes, 41% were fatal, 31% were disabling, and 24% were nondisabling, with no significant treatment-related differences. Stroke subtype affected prognosis: 60% of patients with primary intracranial hemorrhage died and 25% were disabled versus 17% dead and 40% disabled with nonhemorrhagic infarctions. Patients with moderate or severe residual deficits showed significantly decreased quality of life. Advanced age, lower weight, prior cerebrovascular disease or hypertension, systolic and diastolic blood pressures, randomization to tissue plasminogen activator, and an interaction between age and hypertension were significant predictors of intracranial hemorrhage. Conclusions Stroke remains a rare but catastrophic complication of thrombolysis. Additional studies should assess the net clinical benefit of thrombolysis in high-risk subgroups, particularly the elderly and patients with prior cerebrovascular events.