BACKGROUND AND OBJECTIVES: The relationship between ejection fraction (EF), N-terminal pro-brain natriuretic peptide (NT-proBNP) levels and renal function is unknown as stratified by heart failure (HF) type. We investigated their relation and the prognostic value of renal function in heart failure with preserved ejection fraction (HFpEF) vs. reduced ejection fraction (HFrEF). MATERIALS AND METHODS: NT-proBNP, glomerular filtration rate (GFR), and EF were obtained in 1,932 acute heart failure (AHF) patients. HFrEF was defined as EF<50%, and renal dysfunction as GFR<60 mL/min/1.73 m² (mild renal dysfunction: 30≤GFR<60 mL/min/1.73 m²; severe renal dysfunction: GFR<30 mL/min/1.73 m²). The primary outcome was 12-month all-cause death. RESULTS: There was an inverse correlation between GFR and log NT-proBNP level (r=−0.298, p<0.001), and between EF and log NT-proBNP (r=−0.238, p<0.001), but no correlation between EF and GFR (r=0.017, p=0.458). Interestingly, the prevalence of renal dysfunction did not differ between HFpEF and HFrEF (49% vs. 52%, p=0.210). Patients with renal dysfunction had higher 12-month mortality in both HFpEF (7.9% vs. 15.2%, log-rank p=0.008) and HFrEF (8.6% vs. 16.8%, log-rank p<0.001). Multivariate analysis showed severe renal dysfunction was an independent predictor of 12-month mortality (hazard ratio [HR], 2.08; 95% confidence interval [CI], 1.40–3.11). When stratified according to EF: the prognostic value of severe renal dysfunction was attenuated in HFpEF patients (HR, 1.46; 95% CI, 0.66–3.21) contrary to HFrEF patients (HR, 2.43; 95% CI, 1.52–3.89). CONCLUSION: In AHF patients, the prevalence of renal dysfunction did not differ between HFpEF and HFrEF patients. However, the prognostic value of renal dysfunction was attenuated in HFpEF patients.