Background: High pressure balloon inflation has been used as a standard technique during stent implantation in practice. However, the efficacy of this strategy is not well established during primary coronary stenting. We evaluated the clinical outcomes at 6 months follow-up according to balloon inflation pressure in patient with acute myocardial infarction (AMI) who underwent primary coronary stenting. Methods: This retrospective study included 117 patients who underwent coronary stent (��� 3.0mm sized) implantation. According to balloon inflation pressure, all patients were divided into 3 groups: Group 1 low pressure (< 12atm), Group 2 moderate pressure (��� 12 to < 16atm), Group 3 high pressure (��� 16atm). The clinical outcomes (include death, non-fatal myocardial infarction, target vessel revascularization) were evaluated at 6 months follow-up. Results: See as a following table. Conclusion: The use of moderate to high pressure balloon inflation during primary coronary stenting did not show better late clinical outcomes.