Frailty has been reported to be significantly associated with adverse health outcomes in people with heart failure (HF).To explore the potential effects of frailty on unplanned readmissions and death in people with HF patients aged 18 years or older.342 HF patients aged 18 years or older from the heart centers of two different tertiary care hospitals located in northwest of China were enrolled between July and December 2020. Frailty was assessed by the Tilburg Frailty Indicator. The patients were followed for unplanned readmissions, and all-cause mortality at 30, 60, as well as 90 days after discharge. Multivariate cox regression models were used to analyze the effects of frailty on 90-day unplanned readmission and death in the patients with HF.Frailty prevalence was 54.7% among 342 HF patients, with a mean age of 64.65 ± 11.90 years. It was found that compared to non-frailty HF patients, the frailty HF patients were older and displayed higher systolic blood pressure, longer duration of HF, more severe cognitive function, and more comorbidities (P < 0.05). On the contrary, the patients in the frail group had a higher incidence of unplanned readmission (73.1% vs. 26.9%, χ2 = 18.87, P < 0.01) and death (100% vs. 0%, χ2 = 6.94, P < 0.01) than those in the non-frail group. Multivariate cox regression analysis showed that frailty could serve as an independent risk factor for 90-day unplanned readmission (HR = 1.469, 95% CI 1.318-1.637, P < 0.01) and 90-day death (HR=2.270, 95% CI 1.091-4.726, P < 0.01) in the patients with HF.Frailty can act as an independent predictor of unplanned readmission and death 90-day after discharge in HF patients aged 18 years or older.Copyright © 2022 Elsevier Inc. All rights reserved.