Background: To investigate the efficacy and safety of low-dose tirofiban in elderly patients undergoing primary percutaneous coronary intervention (PPCI) for acute myocardial infarction (AMI). Methods: One hundred and four patients aged 70 years and above undergoing PPCI for AMI were divided into control (n=52) and study (n=52) groups. All patients received bolus intracoronary injection of tirofiban (10. Âµg/kg), which was followed by intravenous infusion at 0.15. Âµg/kg/min in the control group and at 0.075. Âµg/kg/min in the study group for 24. h. Results: There was no statistically significant difference between the study group and the control group in patients with complete ST segment resolution (84.2% vs. 85.7%, P= 0.851), peak high-sensitive cardiac troponin T level (5.1±1.9 vs. 5.8±2.6. Âµg/L, P= 0.123), scores of thrombus in the infarct-related artery (0.98±0.51 vs. 1.12±0.59, P= 0.214), and patients with TIMI grade 3 flow (86.0% vs. 88.2%, P=0.737) after PPCI. There were no statistically significant differences between the two groups in left ventricular ejection fraction (57.1±6.3 vs. 57.7±6.1, P=0.611) and composite major adverse cardiovascular events rate (P =0.778) at 90 days after PCI. The total bleeding rate in the study group was lower than in the control group (P= 0.048). Conclusion: In elderly patients with AMI undergoing primary PCI, low and standard dose of tirofiban exerts similar effects on platelet aggregation, coronary flow, infarct size, left ventricular systolic function and short-term clinical outcomes. Low dose regimen is associated with a lower bleeding rate than the standard dose. Â© 2015 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ).