Objective:To investigate the correlation between triglyceride-glucose (TyG) index and high on-treatment platelet reactivity (HTPR) during clopidogrel treatment in patients with ischemic stroke.Methods:Patients with ischemic stroke who received maintenance dose of clopidogrel (75 mg/d) in the Department of Neurology, Guangdong Provincial Hospital of Chinese Medicine from January 2017 to March 2021 were retrospectively included. The highest quartile (Q4) of the TyG index was defined as insulin resistance. Platelet reactivity was assessed by thromboelastogram and clopidogrel HTPR was defined as the clot strength induced by adenosine diphosphate (MA ADP) >47 mm. Multivariate regression model was used to analyze the independent correlation between TyG index and platelet reactivity. Results:A total of 83 patients were included. The TyG index showed a linear correlation with MA ADP. The patients were divided into 4 groups according to the quartile of TyG index. The incidence of clopidogrel HTPR increased significantly with the increase of the quartile of the TyG index ( Ptrend=0.017). Multivariate analysis showed that there was a significant independent correlation between insulin resistance and clopidogrel HTPR (odds ratio 4.597, 95% confidence interval 1.285-16.446; P=0.019). Conclusions:In patients with ischemic stroke treated with clopidogrel, the incidence of clopidogrel HTPR gradually increases with the increase of the quartile of the TyG index. The insulin resistance assessed by the TyG index is independently associated with clopidogrel HTPR.