Background@#β-blockers (BBs) are considered primary therapy in stable heart failure (HF) with reduced ejection fraction (HFrEF) without atrial fibrillation (AF); evidence-based benefits of BB on outcome have been documented. However, BBs have not been shown to improve mortality or reduce hospital admissions in HF patients with AF. This study assessed the relationship between BBs at discharge and relevant clinical outcomes in acute heart failure (AHF) patients with AF. @*Methods@#From the Korean Acute Heart Failure Registry, 936 HFrEF and 639 HF patients with preserved ejection fraction (HFpEF) and AF were selected. Propensity score (PS) matching accounted for BB selection bias when assessing associations. @*Results@#BB-untreated patients in the overall cohort of HFrEF and HFpEF had greater deteriorated clinical and laboratory characteristics. In the 670 PS-matched cohort of HFrEF patients, incidences of all clinical events at 60 days and 1 year were not different according to use of BBs. In the 470 PS-matched cohort of HFpEF, rehospitalization and composite outcome at 6 months and 1 year more frequently occurred in non-users of BBs. After adjusting for covariates in the multivariable Cox model of matched cohorts, BB was not associated with clinical outcomes at 60 days and 1 year in HFrEF with AF patients. In HFpEF patients with AF, BB use was associated with reduced 6-month (hazard ratio [HR], 0.38; 95% confidence interval [CI], 0.20–0.74) and 1-year rehospitalization (HR, 0.53; 95% CI, 0.34–0.82). @*Conclusion@#In the HFrEF with AF PS-matched cohort, the use of BBs at discharge was not associated with clinical outcome. However, in HFpEF with AF, the use of BB was associated with reduced rehospitalization during the 6-month and 1-year follow up.