Abstract: AIM:To observe the effectiveness and safety of low-dose tirofiban in patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS) at high altitude. METHODS: A total of 75 patients with NSTE-ACS were randomized into control group (n=37) and tirofiban group (n=38). Patients in both groups were treated with aspirin, clopidogrel and low molecular weight heparin therapy. Patients in tirofiban group were treated with tirofiban ［load dose 0.3 μg/(kg·min)×30 min, maintaining dose 0.05 μg/(kg·min)×72 h］. Platelet count and platelet adhesion rate were measured before and after tirofiban treatment. Incidence of cardiovascular events and hemorrhage within 30 days were recorded. RESULTS: Incidence of cardiovascular events within 30 days in control group was significantly higher than in tirofiban group (22% vs. 5%, P<0.05). Incidence of hemorrhage was similar between groups (5% vs. 8%, P>0.05). Platelet adhesion rate was significantly reduced in tirofiban group but no similar change was seen in control group. No reduction of platelet count was observed in either group. CONCLUSION: Treatment with low-dose tirofiban is an effective and safe strategy for patients with NSTE-ACS at high altitude.