Background <p>Inflammation and nutritional status play important roles in the progression and prognosis of heart failure with reduced ejection fraction (HFrEF). The C-reactive protein-to-albumin ratio (CAR) has recently emerged as a potential prognostic biomarker integrating both inflammatory and nutritional pathways. This study evaluated the prognostic significance of admission CAR for predicting three-month mortality in patients hospitalized with acute HFrEF.</p> Methods <p>A prospective single-center study was conducted among patients admitted with acute HFrEF. CAR was calculated at hospital admission using serum C-reactive protein and albumin levels. Demographic and clinical variables were analyzed, and multivariable regression was performed to determine the independent prognostic value of CAR. Receiver operating characteristic (ROC) curve analysis was used to evaluate predictive performance and determine the optimal cutoff value for mortality prediction.</p> Results <p>Admission CAR values were significantly higher in patients who died during the three-month follow-up period. After adjustment for demographic and clinical confounders, CAR remained an independent predictor of short-term mortality. Compared with CRP and albumin assessed individually, CAR demonstrated superior prognostic performance. The optimal CAR cutoff value for predicting three-month mortality was 6.7, with a sensitivity of 75.8% and specificity of 62.5%. The area under the ROC curve was 0.713, indicating moderate discriminative ability. The prognostic significance of CAR remained evident despite the high prevalence of diabetes mellitus within the study population.</p> Conclusion <p>Admission CAR is a reliable and independent predictor of three-month mortality in acute HFrEF. Owing to its low cost, wide availability, and ease of calculation, CAR may serve as a practical bedside biomarker for early risk stratification and management optimization in high-risk patients.</p>