AIMS: There have been no investigations of the prevalence and clinical implications of coexistence of anaemia and frailty in older patients hospitalized with heart failure (HF) despite their association with adverse health outcomes. The present study was performed to determine the prevalence and prognostic value of the coexistence of anaemia and frailty in hospitalized older patients with HF. METHODS AND RESULTS: We performed post hoc analysis of consecutive hospitalized HF patients ≥65 years old enrolled in the FRAGILE-HF, which was the prospective, multicentre, observational study. Anaemia was defined as haemoglobin < 13 g/dL in men and <12 g/dL in women, and frailty was evaluated according to the Fried phenotype model. The study endpoint was all-cause mortality. Of the total of 1332 patients, 1217 (median age, 81 years; 57.4% male) were included in the present study. The rates of anaemia and frailty in the study population were 65.7% and 57.0%, respectively. The patients were classified into the non-anaemia/non-frail group (16.6%), anaemia/non-frail group (26.4%), non-anaemia/frail group (17.7%), and anaemia/frail group (39.3%). A total of 144 patients died during 1 year of follow-up. In multivariate analyses, only the anaemia/frail group showed a significant association with elevated mortality rate (adjusted hazard ratio, 1.94; 95% confidence interval, 1.02-3.70; P = 0.043), compared with the non-anaemia/non-frail group after adjusting for other covariates. CONCLUSIONS: Coexistence of anaemia and frailty are prevalent in hospitalized older patients with HF, and it has a negative impact on mortality.