Objective:To investigate the incidence of aspirin and clopidogrel resistance in patients with coronary artery disease received percutaneous coronary intervention (PCI),and provide evidence for the individualized anti-platelet treatment. Methods:Two hundreds patients with defined coronary artery disease who have received PCI were recruited in this study. Platelet aggregations (PLAA and PLADP) 1 mmol/L arachidonic acid (AA) and 5 μmol/L adenosine diphosphate (ADP) were determined using the light transmission aggregometer (LTA). Aspirin and clopidogrel resistance were defined as PLAA >20% and PLADP >40%,respectively. Results:None of the patients was resistant to aspirin in the recruited subjects;the mean PLAA of the recruited patients was (2.63 ± 2.40)%. Forty four patients (22.0%) were resistant to clopidogrel,and the mean PLADP of the non-responders was (47.16 ± 5.82)%;by contrast,156 patients (78.0%) were sensitive to clopidogrel,and the mean PLADP of the responders was (25.62 ± 8.71)%. Conclusion:Aspirin resistance is rare,while clopidogrel resistance is much common in patients with coronary artery disease,which suggests that individualized anti-platelet treatment should be initiated targeting patients with clopidogrel resistance.