Objective <p>This study aims to investigate the utility of red blood cell distribution width-albumin ratio (RAR) for predicting mortality in patients with cardiac diseases.</p> Methods <p>PubMed, Scopus, Embase, and Web of Science databases were systematically searched for studies reporting the association between RAR and mortality in cardiac patients. The search limits were from inception of databases to 20th December 2024. Meta-analysis was conducted for short-term (up to 30 days) and long-term (&gt; 30 days) mortality.</p> Results <p>The analysis of the eight eligible studies showed that per unit increase in RAR [odds ratio (OR): 1.31 95% confidence intervals (CI): 1.16, 1.49 I² = 68%] as well as higher cut-offs of RAR (OR: 1.82 95% CI: 1.51, 2.19 I² = 17%) were associated with a significant increase in the risk of short-term mortality in cardiac disease patients. On the pooled analysis, per unit increase in RAR (OR: 1.68 95% CI: 1.18, 2.38 I² = 99%) and higher levels of RAR (OR: 2.07 95% CI: 1.80, 2.37 I² = 64%) were associated with a significant increase in the risk of long-term mortality. Meta-regression using sample size, age, male gender, diabetes mellitus, hypertension, pulmonary disease, red blood cell distribution width, albumin levels, and RAR cut-off as moderators did not reveal significant associations. GRADE assessment showed that certainty of evidence was ‘very low’.</p> Conclusions <p>RAR can be a potential biomarker for predicting mortality in patients with cardiac disease.</p>