Triglyceride glucose (TyG) index is considered a new surrogate marker of insulin resistance that associated with the development of vascular disease. The aim of this study was to evaluate the prognostic value of TyG index in patients with acute myocardial infarction (AMI). A total of 3181 patients with AMI were included in the analysis. Patients were stratified into 2 groups according to their TyG index levels: the TyG index <8.88 group and the TyG index ≥8.88 group. The incidence of major adverse cardiovascular events (MACEs) during a median of 33.3-month follow-up were recorded. Multivariable Cox regression models revealed that the TyG index was positively associated with all-cause death HR (95% CI): 1.51 (1.10,2.06), p = 0.010, cardiac death HR (95% CI): 1.68 (1.19,2.38), p = 0.004, revascularization HR (95% CI): 1.50 (1.16,1.94), p = 0.002, cardiac rehospitalization HR (95% CI): 1.25 (1.05,1.49), p = 0.012, and composite MACEs HR (95% CI): 1.19 (1.01,1.41), p = 0.046 in patients with AMI. The independent predictive effect of TyG index on composite MACEs was mainly reflected in the subgroups of male gender and smoker. The area under the curve (AUC) of the TyG index predicting the occurrence of MACEs in AMI patients was 0.602 95% CI 0.580,0.623; p < 0.001. High TyG index levels appeared to be associated with an increased risk of MACEs in patients with AMI. The TyG index might be a valid predictor of cardiovascular outcomes of patients with AMI. Retrospectively registered. •Insulin resistance correlates significantly with adverse cardiovascular outcomes.•Triglyceride glucose index is a reliable, and valid surrogate marker of insulin resistance.•High TyG index level is associated with an increased risk of MACEs in patients with AMI.