Objective: This study aimed to examine gender-based differences in epidemiology, clinical characteristics, and management of consecutivepatients with heart failure with mid-range ejection fraction (HFmrEF) and heart failure with preserved ejection fraction (HFpEF).Methods: The APOLLON trial (A comPrehensive, ObservationaL registry of heart faiLure with mid-range and preserved ejection fractiON) is amulticenter, cross-sectional, and observational study. Consecutive patients with HFmrEF or HFpEF who were admitted to the cardiology clinicswere included (NCT03026114). Herein, we performed a post-hoc analysis of data from the APOLLON trial.Results: The study population included 1065 (mean age of 67.1±10.6 years, 54% women) patients from 11 sites in Turkey. Compared with men,women were older (68 years vs. 67 years, p<0.001), had higher body mass index (29 kg/m2 vs. 27 kg/m2, p<0.001), and had higher heart rate (80 bpmvs. 77.5 bpm, p<0.001). Women were more likely to have HFpEF (82% vs. 70.9%, p<0.001), and they differ from men having a higher prevalence ofhypertension (78.7% vs. 73.2%, p=0.035) and atrial fibrillation (40.7% vs. 29.9%, p<0.001) but lower prevalence of coronary artery disease (29.5%vs. 54.9%, p<0.001). Women had higher N-terminal pro-B-type natriuretic peptide (691 pg/mL vs. 541 pg/mL, p=0.004), lower hemoglobin (12.7 g/dLvs. 13.8 g/dL, p<0.001), and serum ferritin (51 ng/mL vs. 64 ng/mL, p=0.001) levels, and they had worse diastolic function (E/e'=10 vs. 9, p<0.001).The main cause of heart failure (HF) in women was atrial fibrillation, while it was ischemic heart disease in men.Conclusion: Clinical characteristics, laboratory findings, and etiological factors are significantly different in female and male patients with HFmrEFand HFpEF. This study offers a broad perspective for increased awareness about this patient profile in Turkey. (Anatol J Cardiol 2019; 21: 242-52)