BACKGROUND: Although heart failure is a well-known major global public health concern, the general understanding of the clinical status of pediatric heart failure (PHF) is inadequate. Therefore, this study aims to enhance the general understanding of clinical characteristics across different PHF age groups and provide references for improving PHF treatment strategies. METHODS: This multicenter retrospective cohort study involved patients from 20 Chinese provinces, primarily including hospitalized patients (aged ≤18 years) diagnosed with heart failure between January 2013 and December 2022. The study subjects were categorized into 4 groups: neonatal, infant and toddler, young children, and adolescent. RESULTS: Herein, 2903 hospitalized patients with PHF were included. Significant differences were observed across age groups in clinical characteristics, auxiliary examination results, comorbid diagnoses, and hospitalization outcomes. After adjusting for covariates, the odds of in-hospital death were significantly lower in the infant and toddler (odds ratio [OR], 0.46 [95% CI, 0.25-0.85]), young children (OR, 0.39 [95% CI, 0.18-0.85]), and adolescent (OR, 0.34 [95% CI, 0.13-0.87]) groups compared with the neonatal group. Furthermore, the odds of cardiovascular adverse events were significantly higher in the young children (OR, 1.91 [95% CI, 1.62-2.88]) and adolescent (OR, 2.16 [95% CI, 1.15-4.06]) groups compared with the neonatal group. Additionally, regarding the odds of a bad Ross class, the adolescent group had 1.85 times higher odds (95% CI, 1.11-3.09) compared with the neonatal group, 2.36 times (95% CI, 1.67-3.35) higher odds compared with the infant and toddler group, and 1.45 times (95% CI, 1.05-2.02) higher odds compared with the young children group ( CONCLUSIONS: This study emphasizes the importance of age-specific stratification in PHF management, revealing distinct clinical and prognostic differences across various developmental stages. REGISTRATION: URL: https://www.chictr.org.cn. Unique identifier: ChiCTR2300078262.