Aims: Antiplatelet treatment could cause a change in plasma levels of platelet microRNAs (miRNAs).However, it is not clear whether the plasma level of platelet miRNAs can predict clinical outcomes of antiplatelet treatment.The present study aimed to evaluate the association of plasma miR-16, miR-21, miR-126, miR-26b, and miR-223 with the risk of clinical outcomes in dual antiplatelet-treated patients after percutaneous coronary intervention (PCI).Methods and results: A total of 491 Han Chinese patients who had received PCI and dual antiplatelet therapy were sequentially recruited to the study and followed for up to one year.Plasma concentrations of five candidate miRNAs early the next morning after PCI were determined by quantitative reverse transcription PCR.The effect of the plasma miRNA level on major adverse cardiovascular events (MACE) within one year and bleeding within six months were assessed.We found that a higher plasma miR-126 level was significantly associated with a higher risk in terms of time-to-MACE.When compared with the plasma miR-126 level in the first three quartiles, the hazard ratio (HR) for the plasma miR-126 level in the fourth quartile was 2.61 (95% CI: 1.32-5.18, p=0.006).Multivariable Cox regression analysis showed that diabetes mellitus, ejection fraction, hypertension and a higher plasma miR-126 level were independent risk factors for MACE.Plasma miR-223 level was not an independent predictive marker for MACE.There was no significant association between the level of 5 plasma miRNAs and bleeding events during six-month follow-up.Conclusions: Based on these results, we suggest that plasma miR-126 could be a potential marker for predicting major adverse cardiac events in patients after PCI.