Background: The aim of this study is to carify the combined effect of manual thrombectomy and intralesional(IL) administration of a bolus dose of abciximab using thrombectomy device during percutaneous coronary intervention (PCI) in the patient with ST segment elevation myocardial infarction(STEMI) due to thrombotic total obstruction of culprit artery. Methods: We studied 27 patients with STEMI who underwent primary PCI after administration of an IL abciximab bolus (0.25 mg/kg) (IL Group, 14 pateints, 63.1짹11.9 years) using Thrombuster device after thrombectomy, and control patients who were treated by intravenous (IV) bolus and conventional maintainace dose(10 microgram/kg for 12 hours) of abciximab (IV Group, 13 patients, 67.2짹10.1 years) prior to balloon angioplasty. The soluble CD40 ligand(sCD40L), Myocardial blush grade(MBG) after PCI, incidence of bleeding complication, and in-hospital, 6, 12 months major adverse cardiac event (MACE; death, myocardial infarction, urgent revascularization) were assessed. Results: There were no significant differences between two groups with regard to baseline clinical, and angiographic characteristics. The dosage of abciximab was significantly higher in IV group than IL group(29.8짹4.5 mg vs. 11.9짹5.8 mg, P<0.01). The success rate of intervention also showed no significant differences between two groups. The incidence of no reflow phenomenon was significantly higher in IV group(6 vs 1, p<0.05). The sCD40L level was significantly lower in IC group than IV group(2127.3짹1437.0 pg/mL vs. 948.5짹1238.0 pg/mL, P<0.05). MBG after primary PCI were significantly higher in IL group than IV group(2.5짹1.7 vs. 1.1짹1.4, P<0.01). The incidence of bleeding complication showed no significant differences, but lower in IL Group compared with IV Group (3 vs 1). The length of in-hospital stay was significantly longer in IV group than IL group(8.7짹4.3 day vs. 4.9짹1.5, P=0.001). The incidence of in-hospital death ,6 and 12 months MACE were not significantly different. Conclusion: The manual thrombectomy plus IL administration of abciximab using thrombectomy device acutely increased MBG, decreased no reflow phenomenon during PCI, bleeding complication and hospital stay in patients with STEMI due to thrombotic total occlusion. Further large scale studies are warranted.