Heart failure HF is a common disease in elderly patients, particularly in those presenting as readmission for worsening HF. While recent studies have revealed mortality-associated factors in this population, little is known about prognostic factors associated with worsening HF. To investigate this clinical evidence gap in patients aged over 75 years, we retrospectively investigated 165 patients hospitalized for HF at Showa University Hospital, of whom 65 39.4 were readmitted for worsening HF. We extracted the candidate variables based on univariate analysis, and then elucidated the independent prognostic factors by multivariate analysis. Compared with non-readmitted patients, readmitted patients with worsening HF had lower left ventricular ejection fraction LVEF 39 vs. 50 , P 0.002 and body mass index BMI 19.9 kg/m 2 vs. 21.4 kg/m 2 , P 0.007 , higher levels of B-type natriuretic peptide BNP 478 pg/ml vs. 198 pg/ml, P 0.001 , and heart rate HR 71.0 beats/min vs. 67.0 beats/min, P 0.021 upon discharge during the primary admission. Multivariate logistic analysis identi ed LVEF 40 , BMI 21 kg/m 2 , BNP ≥ 500 pg/ml, Charlson score ≥ 3, and HR ≥ 70 beats/min upon initial discharge as independent prognostic factors. Based on these factors, readmission for worsening HF was more frequent in those with our proposed risk score of ≥ 3.0 than in those with a risk score 3.0 P 0.001 , and we suggested ve prognostic factors for HF patients over 75 years old. Our proposed risk score combines these factors and might predict readmission for worsening HF in the elderly population.