Background: We previously reported that CYP3A5 polymorphism is associated with vulnerability to drug interaction via CYP3A in clopidogrel users who underwent bare-metal stent implantation. Lipophilic statins such as atorvastatin, simvastatin and lovastatin need metabolism via CYP3A and are potentially considered to be related with clopidogrel resistance. We analyzed the influence of CYP3A5 polymorphism in patients who were coadministered with clopidogrel and lipophilic statin for 6months after drug-eluting stent (DES) implantation. Methods and results: We compared clinical outcomes of patients within six months after successful coronary angioplasty with drug-eluting stent according to their CYP3A5 genotype. The primary end-point was a composite atherothrombotic events (cardiac death, myocardial infarction and non-hemorrhagic stroke) within 6 months after stent implantation. Genotyping was completed in 373 cases (27%) of total gene samples (complete genotyping and final results will be available at the meeting) and we selected 163 patients who took both clopidogrel and lipophilic statin (atorvastatin, simvastatin or lovastatin) simultaneously for six months. Sixty five patients had expressor genotypes (*1*1 and *1*3, 39.9%) and 98 patients (*3*3, 60.1 %) had nonexpressor genotype. These findings were consistent with Hardy -Weinberg expectations. There were no significant differences in clinical and angiographic characteristics between two groups. Atherothrombotic events were occurred only in nonexpressor group (n=2). There were one case of cardiac death and one case of myocardial infarction. Expressor group didn���t have any atherothrombotic events during 6 month follow-up. Conclusion: CYP3A5 polymorphism seems to be a potential cause of clopidogrel drug interaction in patients who take a medicine metabolized via CYP3A system. Further studies are needed.