There is an evidence gap regarding the predictive accuracy of the triglyceride-glucose (TyG) index for long-term major adverse cardiovascular events (MACEs) in individuals with high cardiovascular risk. The aim of this investigation was to evaluate the predictive value of the TyG index for long-term MACEs in patients at high cardiovascular risk. In total, 483 patients with high cardiovascular risk were included in this analysis. The study population was separated into 2 groups depending on the occurrence of long-term MACEs. The independent predictors of long-term MACEs in patients with high cardiovascular risk were investigated. The long-term prognostic value of the TyG index in these patients was evaluated in terms of MACEs. Age, male sex, diabetes mellitus, and the TyG index were demonstrated to be independent predictors of long-term MACE occurrence in patients with high cardiovascular risk. The TyG index was independently related to long-term MACEs in patients with high cardiovascular risk (hazard ratio, 1.003; 95% confidence interval [CI], 1.001-1.006; p=0.011). The receiver operating characteristic curve revealed that the optimum value of the TyG index to predict long-term MACEs in the overall study cohort was >9.68, with 65% sensitivity and 63% specificity (area under the curve, 0.71; 95% CI, 0.65-0.77; p<0.001). The TyG index was demonstrated to be an independent predictor of long-term MACE occurrence in patients with high cardiovascular risk who had not been previously diagnosed with cardiovascular disease.