Objective To investigate the association between CYP2C19 polymorphisms and efficacy of clopidogrel in Chinese Han patients with coronary atherosclerotic heart disease.Methods A total of 176 Chinese Han patients who underwent percutaneous coronary intervention and were treated with dual antiplatelet therapy with aspirin and clopidogrel were enrolled.Polymorphisms of CYP2C19 * 2,* 3 were measured by PCR-restriction fragment length polymorphism (PCR RFLP).The correlation between the genetic variants and cardiovascular events was analyzed.Results In the 176 patients,the allele frequencies of CYP2C19 * 2 and * 3 were 34.38％ and 5.97％ respectively,the percent of patients with poor metabolizer genotypes (* 2/* 2,* 2/* 3,* 3/* 3) was 14.20％.Among the 176 patients,11 patients reoccured acute coronary syndrome,1 patient suffered from stroke,and 4 patients had stent thrombosis.The incidence of cardiovascular events was 9.09 ％.Thecumulative incidence of cardiovascular events had no significant differences between poor metabolizer genotype carriers and extensive and intermediate metabolizer genotype carriers (16.00％ vs.7.95％,x2 =1.683,P=0.195).Conclusions The frequencies of CYP2C19 poor metabolizer genotypes are higher in Chinese Han population than in Caucasians,but the incidence of cardiovascular events in Chinese Han population is not increased.