Abstract Introduction Acute bronchiolitis is a pressing public health concern, leading to numerous infant hospitalizations worldwide annually. The notable decrease in bronchiolitis hospitalizations during the COVID‐19 pandemic sparked concerns about a potential resurgence post‐pandemic. Questions also arose about the severity of post‐pandemic cases compared to prepandemic ones. This study aimed to compare bronchiolitis severity before and after the COVID‐19 pandemic, alongside changes in the epidemiology of bronchiolitis viral agents. Material and Methods We conducted a retrospective analysis of medical records concerning infants under 12 months hospitalized for acute bronchiolitis in our pediatric pulmonology department over a period of 5 years: 2 pre‐COVID years (2018−2020), the COVID year (2020), and 2 post‐COVID years (2021−2023). Clinical and laboratory data were collected using standardized forms. Results Hospital admissions exhibited comparable rates pre‐ and post‐COVID but witnessed a decline during the COVID period. Post‐COVID, bronchiolitis severity increased, with longer hospitalization durations ( p < 0.001) and increased oxygen therapy ( p = 0.04), coinciding with a surge in the prevalence of RSV infections ( p = 0.01). Patients testing positive for RSV were significantly younger ( p = 0.005) and exhibited more severe symptoms. Discussion and Conclusion This study reveals a significant increase in bronchiolitis severity and a rise in RSV cases following the COVID pandemic. The implementation of preventive measures such as nirsevimab is crucial to alleviate the burden of respiratory illnesses in vulnerable populations. Continued vigilance and research are needed to address the evolving challenges of bronchiolitis in the post‐COVID era.