Background Glycoprotein (GP) Ⅱb/Ⅲa antagonist has been shown its efficacy and safety in high-risk patients with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention (PCI). Whether GP Ⅱb/Ⅲa antagonist is as effective and safe in older patients (≥65 years old) as in younger patients remains unclear. Objectives Our objective was to determine whether GP Ⅱb/Ⅲa antagonist tirofiban was effective and safe in patients aged ≥65 years who underwent PCI. Methods From September 2006 to August 2008,622 patients with non-ST-elevation ACS (NSTE ACS) were randomized to receive either tirofiban (n=313) or placebo (n=309). The infusion duration was 48 hours for both groups. Incidence of major adverse cardiac events (MACE) was assessed at 180 days. Incidence of bleeding was monitored through 24 hours after trial therapy was discontinued. Results The incidence of MACE for the tirofiban group versus the placebo group was 7.3% vs 12.6% (P<0.05). Among these MACE,death rate was 2.6% vs 4.6% (P=0.198),non-fatal MI was 3.8% vs 6.5% (P=0.150),and target vessel revascularization was 1.3% vs 1.6% (P=0.751),in the two groups,respectively. The total bleeding rate for the tirofiban group versus the placebo group was 28.1% vs 6.8% (P<0.05). The TIMI major and minor bleeding rates for the tirifiban versus the placebo group were 2.2% vs 1.6% (P>0.05) and 25.9% vs 5.2% (P<0.05),respectively. Conclusions Tirofiban appears to be effective and safe in older patients with ACS who underwent PCI. Background Glycoprotein (GP) IIb / IIIa antagonist has been shown its efficacy and safety in high-risk patients with acute coronary syndrome (ACS) who underwent percutaneous coronary intervention (PCI). Whether GP IIb / IIIa antagonist is effective and safe in older Patients (≥65 years old) as in younger patients remains unclear. Objectives Our objective was to determine whether GP Ⅱb / Ⅲa antagonist tirofiban was effective and safe in patients aged ≥65 years who underwent PCI. Methods From September 2006 to August 2008,622 Patients with non-ST-elevation ACS (NSTE ACS) were randomized to either either tirofiban (n = 313) or placebo (n = 309). The infusion duration was 48 hours for both groups. Incidence of major adverse cardiac events (MACE) was assessed at 180 days. Incidence of bleeding was monitored through 24 hours after trial therapy was discontinued. Results The incidence of MACE for the tirofiban group versus the placebo group was 7.3% vs 12.6% (P <0.05). Among these MACE, dea The rate of non-fatal MI was 3.8% vs 6.5% (P = 0.150), and the target vessel revascularization was 1.3% vs 1.6% (P = 0.751) in the two groups , respectively. The total bleeding rate for the tirofiban group versus the placebo group was 28.1% vs 6.8% (P <0.05). The TIMI major and minor bleeding rates for the tirifiban versus the placebo group were 2.2% vs 1.6% (P> 0.05) and 25.9% vs 5.2% (P <0.05), respectively. Conclusions Tirofiban appears to be effective and safe in older patients with ACS who underwent PCI.