Acute heart failure (AHF) in children is a critical condition with significant morbidity and mortality. Renal impairment, a frequent comorbidity in pediatric AHF, complicates clinical management and worsens outcomes. This review explores the complex interplay between AHF and renal dysfunction, emphasizing the pathophysiological mechanisms underpinning cardiorenal interactions in children. It highlights the role of neurohormonal dysregulation, hemodynamic instability, and inflammatory pathways in precipitating renal impairment. Current diagnostic challenges, including limitations in pediatric-specific biomarkers for renal injury and functional assessment, are discussed. Furthermore, the article evaluates the impact of renal impairment on therapeutic strategies for AHF, such as fluid management, diuretics, and advanced interventions like extracorporeal therapies. Evidence from recent studies and clinical trials is synthesized to provide a comprehensive understanding of this critical intersection. The review underscores the urgent need for pediatric-specific research to optimize diagnosis, risk stratification, and individualized treatment approaches for children with AHF complicated by renal impairment. By addressing these gaps, the findings aim to guide clinicians in improving patient outcomes and inform future research priorities in pediatric cardiology and nephrology.