Background and aimsThis study was conducted to verify whether serum cholinesterase (ChE) is useful in predicting prognosis and discriminating undernutrition status compared to existing low-nutrition indices of blood chemical tests in patients with heart failure (HF). Methods and resultsA total of 1617 patients (1204 older patients) with HF who evaluated ChE during hospitalization were recruited for this study. The primary outcome was all-cause death, and multivariate survival analysis was performed. We drew a receiver operating characteristic curve for all-cause death, some undernutrition status, such as low body mass index, thin mid-upper arm circumference, low grip strength, and slow gait speed. The area under the curve was used to compare the predictive ability of ChE with some existing nutritional parameters, such as blood biochemical tests, controlling nutritional status (CONUT), and the geriatric nutritional risk index (GNRI). After adjusting for 29 variables, higher ChE significantly decreased the risk of all-cause death (per 10 increase, hazard ratio: 0.975, 95% confidence interval: 0.952–0.998), and this trend was maintained for older patients (per 10 increase, hazard ratio: 0.972, 95% confidence interval: 0.947–0.997). ChE was moderately correlated with CONUT and GNRI, but the predictive ability for all-cause death was higher for ChE relative to both scores. ChE tended to have an almost consistently high predictive ability compared with other blood biochemical tests. ConclusionsChE was associated with all-cause death and an almost consistently higher predictive ability for all-cause death and undernutrition status in comparison to existing blood chemical tests and nutritional scores.