<p>Several studies have illustrated the association of the triglyceride glucose (TyG) index with in-hospital and intensive care unit (ICU) mortality. However, no studies have compiled this evidence and reached a conclusion. This study aimed to quantify the association of the TYG index with the risk of in-hospital and ICU mortality. An extensive search of databases including PubMed, Scopus, and Web of Science, was performed up to 21 Jan 2024. Nineteen studies were included in the meta-analysis. The outcomes were in-hospital mortality in 18 studies and ICU mortality in 8 studies. Among the 42,525 participants, 5233 in-hospital and 1754 ICU mortality cases were reported. The pooled analysis revealed that each unit increase in the TYG index was associated with a 33% and 45% increase in the risk of in-hospital (RR = 1.33; 95% CI: 1.23, 1.43; <i>I squared</i> = 90.3%) and ICU (RR: 1.45; 95% CI: 1.25, 1.67; <i>I squared</i> = 44.8%) mortality, respectively. Subgroup analysis revealed a stronger association between the TYG index and the risk of in-hospital mortality in patients with cardiovascular diseases than in those with cerebrovascular diseases (P_{heterogeneity between Groups} = 0.014). The findings of this study showed a positive association between the TyG index and the risk of in-hospital and ICU mortality. (PROSPERO registration ID: CRD420245414390).</p>