Introduction: Health-related quality of life (HRQoL) is an important part in managing patients with heart failure (HF). However, the influence of clinical factors on HRQoL in HF remains limited. Hypothesis: This study aimed to examine HRQoL changes based on gender and left ventricular ejection fraction (LVEF) among patients with HF. Methods: A total of 199 patients hospitalized for acute HF (mean age, 71±14 years; men:women=119:80; mean LVEF=42±16) were enrolled in a prospective way from Jan 2022 to Jan 2023. Baseline and 4-month follow-up Kansas City Cardiomyopathy Questionnaire (KCCQ) scores were assessed. Patients were categorized into 4 subgroups: Group 1, women with LVEF≥50% (n=37); Group 2, men with LVEF≥50% (n=26); Group 3, women with LVEF<50% (n=43); Group 4, and men with LVEF<50% (n=93). Results: Women demonstrated lower KCCQ clinical and overall summary scores than men at baseline (p=0.003, 0.004, respectively) and 4-month follow-up (p=0.029, 0.038, respectively) after adjusting for age and body mass index. In addition, these scores tended to be lower in patients with LVEF ≥50% than those with LVEF <50% at both baseline and follow-up (all p<0.05). When we assessed KCCQ scores according to group, group 1 showed the lowest KCCQ overall summary score (KCCQ-OS: 36.9 [IQR 22.9-49.8], p=0.004) and clinical summary score (KCCQ-CS: 37.8 [IQR: 24.5-51.1], p=0.001). Also, the scores for physical limitation, symptom frequency, symptom burden, social limitation, self-efficacy scale, and total symptom score were lowest in Group 1 (all p<0.05). Although HRQoL improved across all groups, the follow-up KCCQ-OS and KCCQ-CS scores remained lowest in Group 1 (KCCQ-OS: 54.0 [IQR 44.3-64.4], p=0.026; KCCQ-CS: 56.5 [IQR: 45.0-63.9], p=0.031). Conclusions: Among patients with HF, women with LVEF≥50% reported significantly worst HRQoL even after HF treatment, suggesting more attention should be paid to HRQoL in managing this specific population during HF treatment.