Background: Several studies have reported that celecoxib improves endothelium-dependent vasodilation and reduces inflammation and neointimal hyperplasia. However, there are some concerns regarding the safety of celecoxib in patients with cardiovascular disease. We performed this prospective, randomized study to evaluate the safety and efficacy of celecoxib in patients who undergoing coronary stent implantation. Methods: A total of 161 patients planned to undergo stent implantation were randomized to celecoxib(n=77) or control group(n=80). Stent implantation was performed using either DES or BMS. Celecoxib was started immediately before coronary intervention(loading dose 400mg) and maintained for 6 months(200mg bid). Aspirin was given indefinitely and plavix, at least for 6 months. High sensitivity C-reactive protein(hs-CRP) levels were measured at baseline and at 24 hours and creatinine kinase(CK-MB) levels at baseline and at 8 and 24 hours after stent implantation. The patients were followed up for the occurrence of death, myocardial infarction(MI), or target lesion revascularization(TLR) at 30 days. Among these patients, 58 patients(celecoxib group n=29, control group n=29) underwent follow-up CAG and were followed up for the occurrence of death, MI or TLR at 6 months. Results: There were no significant clinical, angiographic and procedural differences between the 2 groups. There was no drug related adverse event in celecoxib group. hs-CRP at 24 hours after PCI was significantly lower in celecoxib group than in control(median[interquartile range]: 6.8mg/L[4.0,9.9] vs. 8.7mg/L[5.7,15.5], P<0.01). The change of hs-CRP was significantly smaller in celecoxib group than in control(5.4mg/L[2.8,8.4] vs. 7.0mg/L[4.3,12.9], P<0.05). There was no significant difference in peak CK-MB value and in the development of periprocedural MI between the 2 groups. The indicence of death, MI or TLR at 30 days was similar in both arms. However, the incidence of death, MI, TLR at 6 months was significantly lower in celecoxib group than in control(7.4% vs. 31.0%, p<0.05). Conclusions: Celecoxib is safe and significantly reduced periprocedural inflammatory response and 6-month cardiac event in patients undergoing stent implantation.