AIMS: Real-world evidence about heart failure (HF) medical care for elderly patients is limited. The aim of this study was to clarify the age-dependent associations of HF medications at discharge with clinical outcomes in a super-aged society using a real-world big database. METHODS AND RESULTS: Patients hospitalized with a first episode of acute HF in 2013-2019 were identified in a nationwide claims database in Japan and were analyzed based on the HF medications at discharge. Hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) for clinical outcomes were calculated after adjustment. Among 325,468 patients from 4351 hospitals, 130,230 (40.0 %) were aged ≥ 85 years. All-cause mortality and HF readmission rate within 1 year were 14 % and 23 %, respectively. β-Blockers and angiotensin-converting-enzyme inhibitors or angiotensin II receptor blockers (ACEI/ARB) uses were associated with lower mortality (HR [95 %CI]: 0.84 [0.83,0.86] and 0.73 [0.71,0.74], respectively) and HF readmission (0.98 [0.97,0.99] and 0.89 [0.88,0.90], respectively). The associations were attenuated as the age increased and, in β-blockers use, the favorable associations with mortality and HF readmission were not observed in patients with ≥ 95 years and ≥ 80 years, respectively. In contrast, mineralocorticoid receptor antagonists (MRA) use was associated only with lower HF readmission (0.83 [0.82,0.84]), which was not attenuated with increased age. CONCLUSIONS: The favorable associations of β-blockers and ACEI/ARB uses with mortality and HF readmission were age-dependently attenuated in patients across a broad spectrum of HF in a super-aged society. In contrast, positive impact of MRA use on HF readmission was not attenuated with aging.