Patients with significant residual stenosis after thrombolytic therapy during acute myocardial infarction have higher risk of reinfarction, periinfarction ischemia and sudden death. Early revascularisation can prevent such complications. To find out patients who are at increased risk and are candidates for early angiography 74 patients undergoing angiography after thrombolytic therapy were reviewed. Significant residual stenosis (greater than or equal to 50% diameter reduction) of infarct related artery was present in 85%, high grade stenosis (greater than or equal to 75%) in 58% of patients respectively. The group of patients with preinfarction angina (Canadian class I to IV. 24 hours before infarction) had higher mean residual stenosis than patients without angina (76.5% vs 64%). There was significant difference in presence of preinfarction angina in patients with high grade stenosis and without high grade stenosis (79% and 21% respectively). Thus preinfarction angina can be used to identify patients with higher risk of reocclusion after thrombolytic therapy during acute myocardial infarction. Early coronary angiography and revascularisation can prevent serious complications in these patients.