Background There is a wide variation in the clinical therapeutic activity of clopidogrel,which has mainly been attributed to genetic effects.Recent a study reported that Paraoxonase-1 (PON1) as a key enzyme plays a vital part in clopidogrel bioactivation.The aim of our study was to assess whether PON1 gene polymorphisms are correlation with the low rates of clopidogrel bioactivation and responsible for negative clopidogrel efficacy in patients undergoing selective coronary stent implantation.