The aim of this study is to compare intracoronary (IC) bolus only with IC bolus plus maintenance intravenous (IV) infusion of glycoprotein IIb/IIIa (GP IIb/IIIa) inhibitors with respect to 1-year major adverse cardiac events including mortality, nonfatal myocardial infarction, revascularization, and bleeding events after primary percutaneous coronary intervention (PCI). This is an observational study of 233 consecutive patients who presented with ST-elevation myocardial infarction and underwent primary PCI between April 2009 and December 2012. Patients were grouped into (1) patients who received IC bolus only (n = 102) and (2) patients who received IC bolus plus maintenance IV infusion of GP IIb/IIIa inhibitors (n = 131). In-hospital post procedural myocardial infarction occurred in 4 (1.7 %) of patients. Mortality occurred in one patient who was treated with IV infusion. Major bleeding occurred in only 5 patients, among whom 4 patients had received GP IIb/IIIa inhibitors IV infusion. However, the difference was not statistically significant (P = 0.389). Both univariate analysis and the adjusted model for the potential confounders revealed no significant association between the way of GP IIb/IIIa inhibitors administration and 1-year major adverse cardiac events. Our findings suggested that IV infusion of GP IIb/IIIa inhibitors after the bolus dose is not associated with better 1-year outcome after adjustment for confounding variables. Moreover, IV infusion may increase the risk of major bleedings after primary PCI. This finding implies that the need for IV infusion of GP IIb/IIIa inhibitors in patients undergoing primary PCI is under question.