WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Human respiratory syncytial virus (HRSV) coinfection with other respiratory pathogens frequently occurs in young children with acute respiratory illness. However, the epidemiological patterns and associated disease burden of HRSV coinfections in pediatric populations remain poorly characterized. WHAT IS ADDED BY THIS REPORT?: Analysis of hospitalized children under 5 years in Zhejiang Province from 2018 to 2023 revealed that 20.4% experienced HRSV coinfections, with bacterial coinfections substantially exceeding viral coinfections (14.1% WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Implementation of comprehensive prevention strategies, including vaccination programs, nonpharmaceutical interventions, and enhanced surveillance of multiple respiratory pathogens, is essential to reduce HRSV coinfections and their associated disease burden during periods of high respiratory pathogen circulation.