Background <p>Cardiovascular-kidney-metabolic syndrome (CKM) is associated with an increased risk of mortality among older adults, but the relationship between cognitive function and mortality across different stages of CKM remains unclear. This study investigated the associations between cognitive performance and all-cause mortality among older adults with different stages of CKM syndrome.</p> Methods <p>The current cohort analyzed data from 1155 United States older adults aged ≥ 60 years. Cognitive function was measured using typical cognitive tests. Participants were classified into non-advanced CKM and advanced CKM groups. Weighted regression models were used to explore the association between cognitive function and mortality.</p> Results <p>Following full adjustment for potential confounders, higher cognitive function scores were associated with a decreased risk of all-cause mortality risk in both advanced and non-advanced CKM groups. The highest quartile group exhibited a decreased risk of mortality in cognitive tests ( hazard ratio &lt; 1, <i>P</i> &lt; 0.05). Significant interactions were observed between subgroups of cognitive scores, smoking status, and body mass index.</p> Conclusion <p>Improving cognitive function may lower the risk of mortality among older adults with non-advanced CKM and advanced CKM.</p> Graphical Abstract <p></p>